An H&R Block office in the Bronx has allegedly been used for identity theft with employees or former employees the likely culprits in stealing the identities of at least 20 customers to claim refunds in their name.

A class-action lawsuit has been filed against the company for not taking further steps to protect customers’ security after similar cases occurred in other states, according to The New York Times. In one case, a former Block customer had his $8,499 refund claimed before he could file his taxes last year, while another had her $6,145 refund stolen.

“H&R Block is working diligently with the IRS and other authorities to resolve this situation for clients,” Block said in a statement. “We are standing by our clients and doing everything we can to assist them.”