Business Insider reports payments service Square has been withholding up to 30% of customer payments amid the coronavirus outbreak.
That's infuriated business owners, who have had to lay off employees or miss mortgage payments.
According to Business Insider, Square has been using a tool called reserves, which is used to protect against "risky" transactions.
Such transactions include payment for goods and services that are delivered later, or those in which the customer may ask for a refund.
However, merchants say they haven't had any such transactions flagged.
More than 1,400 of them have petitioned Square to stop withholding the funds.
Square, which is run by Twitter CEO Jack Dorsey, said in a blog post that it uses the tool sparingly.