About 80 million taxpayers are slated to receive stimulus checks this week, but some Americans are expressing frustration because the checks haven't landed in their accounts. One culprit could be whether they filed through tax prep services such as H&R Block or TurboTax and received tax refund anticipation loans, according to a U.S. Treasury Department spokeswoman.

That's because the IRS doesn't have direct deposit information for those taxpayers, the Treasury spokeswoman says. The issue is tied to how tax refund anticipation loans work. These loans are basically advances on a tax refund that you expect from the IRS but which are provided by the tax prep services, which sometimes use credit cards, like H&R Block's Emerald Prepaid MasterCard, to provide the loan to consumers. But that means the IRS may not have the taxpayers' bank information.

Consumers who used a tax prep service and relied on a tax refund anticipation loan should enter their bank account information into the IRS "Get My Payment" site, according to the Treasury Department.

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However, some consumers on Thursday were reporting problems accessing the site, with many reporting to CBS MoneyWatch that they received a "Payment status not available" message, with no option to update their bank account information.

If you did not receive your stimulus check via direct deposit on Wednesday, and filed your taxes through turbo tax or H&R Block, the IRS does not have your direct deposit information on file. If you still want direct deposit, input the information on the IRS website — Nouma ✨ (@naouma_) April 16, 2020

However, both TurboTax and H&R Block said the IRS should have the banking information for its customers.

"The bank account information for TurboTax filers is transmitted to the IRS as a part of the tax return," the company said in a statement to CBS MoneyWatch. "The IRS has the appropriate banking information for all TurboTax filers, which can be used by them to distribute stimulus payments. This is true regardless of whether a customer chose to receive their refund on a debit card, selected refund transfer or other services."

H&R Block said the IRS has "created confusion by not always using clients' final destination bank account information for stimulus payments." It added that it is working with the IRS to get the payments sent directly to its clients.

Taxpayers who recently filed their 2019 taxes may encounter the "Payment status not available" message from the IRS website because the tax agency is still processing their tax returns.

Still, some taxpayers have told CBS that they've already received their 2019 tax refunds, didn't use tax refund loan anticipation service and are still having trouble getting information from the site.

If the IRS doesn't have a taxpayer's direct deposit information, the agency will mail out paper checks, which are slated to be issued starting the week of May 4 until the last batch goes out in September.

To be sure, millions of Americans have received their stimulus payments this week without a hitch. Single taxpayers who earn less than $75,000 will receive $1,200, while married couples who earn less than $150,000 will receive $2,400. Parents of children under 17 will get $500 per child. People who earn above those thresholds will see their payments reduced by $5 for every $100 of income, until the payments phase out at $99,000 of income for single filers and $198,000 for married couples.

The IRS and Treasury created the tracking website and are disbursing the "economic impact payments" less than three weeks after the $2 trillion stimulus bill was signed into law by President Donald Trump.

Yet during that time, millions of workers have lost their jobs, with more than 22 million Americans filing for unemployment in about a month.