Tony Hetherington is Financial Mail on Sunday's ace investigator, fighting readers corners, revealing the truth that lies behind closed doors and winning victories for those who have been left out-of-pocket. Find out how to contact him below.

K.H. writes: I had hoped that following your intervention with Revolut, we could move on.

However, Revolut has messaged my wife, saying that her account has been closed and funds returned 'to source'.

Well, I was that source, and nothing has been returned to me, so where has the money gone?

Flashback: Our story in December pictured alongside Revolut boss Nikolay Storonsky

In December, I reported how Revolut had 'temporarily disabled' your account without notice, trapping £10,000 of your money while it carried out unspecified enquiries for what it said were 'security reasons'.

These words and actions invariably mean that you are suspected of being a criminal money launderer, and you are guilty until proven innocent. You and I both found that Revolut does not reply to emails.

Its published phone number simply offers useless options, none of which allow you to speak to a human being. It has no branches, and its only office in London does not welcome callers or customers.

I finally made contact with this ultra-modern company by sending an old-fashioned signed-for letter by snail mail to Revolut's Russian-born boss Nikolay Storonsky.

This won me a vaguely worded statement explaining how Revolut keeps its customers safe from fraud, sometimes by freezing their account if there is anything it regards as 'suspicious activity'.

With no explanation of what that activity was, Revolut restored your account and your cash. But in the same breath, it seems to have spotted that your wife has an account, so it first froze it and then closed it. About £2,500 of your wife's money vanished.

Revolut unilaterally decided to send her money back to an account you have at Transferwise, so I asked Revolut where the cash had actually gone. And just as importantly, I asked why it should not have been your wife's decision as to where her money went. Suppose, for example, she had struggled to get a refund from a shop, only to have Revolut send the money straight back to the shop's bank.

I never did get an answer to this second question, but it appeared the £2,500 had disappeared because Transferwise had changed its IBAN, the international bank account number used in transfers.

And when the money bounced back to Revolut, it went into a dumping ground holding account where Revolut said it could not find it unless Transferwise, which had not requested or expected the money in the first place, provided details that would allow Revolut to trace it.

This was ridiculous, so I offered to accompany your wife to Revolut's offices and go through its records until we found the missing money. And I asked, would it be OK for me to bring a Mail on Sunday photographer to record the event?

Suddenly, Revolut found the funds, updated the IBAN, and made the transfer to Transferwise, depriving me of a day out at its Canary Wharf offices. But it still refused to explain why it closed your wife's account. 'We cannot disclose details on individual accounts,' I was told.

Which is fair enough – except that your wife had signed a legally binding authority allowing Revolut to do exactly that.

Finally, in December, I described Revolut as a bank. It has asked me to say that it is not a bank, but a 'global financial platform'.

In which case, it might want to correct any false impression customers might get from its own website, which advertises 'a next generation banking experience,' and proclaims: 'Revolut is building a global bank to suit your lifestyle.' Strange lifestyle, strange banking experience.

Why does the Revenue keep trying to pay me?

P.K. writes: I need your help in my unusual dispute with Revenue and Customs – they wish to pay me refunds and grant me tax allowances to which I know I am not entitled.

Money for nothing: Revenue staff have now spring-cleaned your own records and taken steps to make sure the same mistake does not happen again

You are 73, a retired engineer and teacher, and your tax affairs are straightforward. Out of the blue, you received a claim form from the Revenue, and when you checked your online tax account, it showed you were due a refund of £1,385.

This was apparently tax overpaid on your business income – except you have no such income.

After lots of phone calls from you, the tax office deleted the refund from your account. But now the same thing has happened again.

You have been invited to reclaim £461, and the Revenue has changed the tax it collects from your pension because, it says, 'you now get job expenses worth £2,310'. Again, you have tried to alert the tax office to this, but without success.

I asked officials at the Revenue head office to investigate, and they told me: 'We received an online tax return for a different customer which used an incorrect reference number.'

In short, a firm of accountants with no connection to you has put your tax reference on their client's file by mistake. Revenue staff have now spring-cleaned your own records and taken steps to make sure the same mistake does not happen again.

If you believe you are the victim of financial wrongdoing, write to Tony Hetherington at Financial Mail, 2 Derry Street, London W8 5TS or email tony.hetherington@mailonsunday.co.uk.

Because of the high volume of enquiries, personal replies cannot be given. Please send only copies of original documents, which we regret cannot be returned.