Buy-now-pay-later apps such as Affirm, Afterpay, Klarna, and Quadpay have grown in popularity since the start of the pandemic. However, an increasing number of users report being hit with unforeseen fees and struggling to get refunds processed for product returns, according to the Los Angeles Times.

Young people are often lured in by celebrities who advertise the apps as modern alternatives to credit cards. But experts say the buy-now-pay-later trend could lead to debt problems and poor credit.

Thousands of shoppers have filed grievances with agencies that report to the Consumer Financial Protection Bureau (CFPB) and Better Business Bureau (BBB) alleging that funds continue to be drawn from their accounts for returned items, among other complaints.

Regulators are taking note in the U.S., Australia, and Europe. Klarna, one of the largest such apps, received 676 complaints over the last year, and will now begin reporting its usage data to credit bureaus in the UK to help offset future regulations aimed at protecting young people from debt, according to CNBC.

The U.S. House Financial Services Committee’s Task Force on Financial Technology sponsored a hearing Tuesday with consumer advocates and industry heads to discuss the advantages and disadvantages of the loans.

“It is difficult to shop online without seeing a ‘buy now, pay later’ option,” said Representative Stephen Lynch (D-MA). “However, these products also raise important questions about use of consumer data, the exploitation around spending patterns, the application of lending laws and the potential for unsustainable levels of consumer debt.”

A recent Credit Karma survey discovered around 38 percent of buy-now-pay-later customers missed at least one payment, and 72 percent of users said their credit score subsequently dropped.