I recently got an RFE on my 1 485 so I contacted the law office to request the old papers to be able to answer the RFE.

I recently got an RFE on my 1 485 so I contacted the law office to request the old papers to be able to answer the RFE. They law office had no idea of my existence. They had never paid too much attention to my case from the start and after going back and forth with emails they were still not able to help me with my questions since they were too lazy to look up my records. I gave up on them and then out of the blue they send me an invoice for $750 after 8 years saying they had forgotten to bill it in 2007. Its not about the money but Do I have to pay a firm for such a shabby service that they have me begging for every little thing and they still don't help ? After 8 years does that invoice even hold any statute? Appreciate an answer.