Property owners in Massachusetts and across the United States say they are being threatened with foreclosure and assessed unfair fees by lenders even after signing agreements with those companies to make lower mortgage payments and stay in their homes.

Eight Bank of America borrowers - including two from Massachusetts - have filed a lawsuit against the nation’s largest bank, alleging it violated loan modification contracts, wrongly attempted to collect money from them, damaged their credit, and initiated wrongful foreclosure actions. They expect others to join the suit and are seeking class-action status.

Borrowers and housing advocates say the problem is a further indication of the mortgage industry’s ongoing woes.

Bank of America declined to comment.

Loan problems typically occur when one department at a lending company approves a modification - permanently lowering a homeowner’s mortgage obligation through interest rate or principal reductions - but does not accurately update the borrower’s records, housing advocates say. As a result, other departments may continue to classify the customer’s account as delinquent.

The frequency of such errors is a matter of some disagreement. Faith Schwartz, executive director of the nonprofit Hope Now Alliance, which represents businesses and housing counselors in the mortgage industry, said she was not aware of any serious issues with completed loan modifications.

“That is not something that has come up often,’’ Schwartz said.

But Kathleen Day, spokeswoman for the nonprofit Center for Responsible Lending, based in North Carolina, said the problem is widespread.

“It is all too common for banks to enter a loan mod and then try to foreclose on people and try to harangue them for money,’’ Day said. “All the evidence shows that servicing procedures and record keeping are just a mess. It ranges from disarray to out-and-out fraud.’’

Officials from the Treasury Department, which oversees the government-sponsored Home Affordable Modification Program, said homeowners should not experience difficulties with lenders after signing permanent modification contracts.

“If any instances arise that show that servicers have not been following guidelines, they are required to remedy their process and assess if any borrowers have been potentially impacted,’’ said Andrea Risotto, a Treasury spokeswoman.

Shennan Kavanagh, a lawyer with the Boston law firm Roddy Klein & Ryan - which filed the suit - said it is especially traumatic for homeowners who have gone through the stressful monthslong modification process to find they could still be at risk of losing their properties.

“There is complete and utter chaos in the servicing industry,’’ Kavanagh said. “These are supposed to be the lucky folks.’’

The complaints come as a group of state attorneys general negotiate with major US lenders following a yearlong investigation into allegations of sloppy and fraudulent foreclosures.