Cryptocurrency exchange HitBTC has yet to respond to accusations it deliberately froze account withdrawals on Jan. 1, days prior to entrepreneur Trace Mayer’s Proof of Keys event.

In a series of tweets, Mayer joined names such as crypto advocate John McAfee in voicing concern and even suspicion about HitBTC after users reported being unable to withdraw their funds.

On both Twitter and Reddit, users acknowledged that the practice of freezing accounts had occurred often in the past, and that the timing two days before Proof of Keys was not necessarily deliberate.

Proof of Keys, which Mayer announced last month, calls on cryptocurrency investors to remove their coins from third party platforms in order to take control of their private keys.

This, he argues, will educate them about holding reserves themselves and not relying on middlemen, contributing to the spirit of Bitcoin (BTC) and furthering adoption.

“Has (HitBTC) failed (Proof of Keys)?” he asked on Twitter, writing:

“I do not have an account. Asked a friend to initiate a withdrawal. BEWARE!... Result: ‘Withdrawals are temporarily disabled on your account.’”

At press time on Wednesday, HitBTC had not addressed Mayer’s query publicly, while others added to the controversy surrounding the exchange on social media.

McAfee, who in September announced a concerted effort to counter what he called corruption at HitBTC, appeared unsurprised by the events.

“I warned everyonw [sic] more than a dozen times. Don't sign up. Don't use it,” he tweeted, adding:

“Withdtaw [sic] your funds. I was trashed for calling out HitBT [sic] as a corrupt cimpany [sic]. Tough sh*t. You had six months warning from me to withdraw your funds. Do not ask me to help you now.”

Bitfi, the cryptocurrency wallet manufacturer endorsed by McAfee that previously faced a publicity battle of its own, joined the furore, claiming HitBTC was stealing money from its users.

Reddit user pedxs described on Jan. 1 how his withdrawals had been blocked after reportedly completing Know Your Customer (KYC) requirements. The user stated that after HitBTC had written in an email that “No further automated restrictions will be applied,” the exchange has allegedly blocked his BTC withdrawals and frozen his account.

Another Reddit user posted about his locked funds after submitting KYC requirements, leading to a purported HitBTC support person, user paola_balzano, to comment asking for a support ticket number to provide a follow up. The original poster declined, underlining that her or she wanted to go through the official support channels.

HitBTC has been approached for comment through their media email, but has not responded as of press time.