advice needed regarding law firm breaching pdpa

long story short, i owe some money from around 8-10 years ago.

creditor got a law firm to chase for debt, and we were communicating via email for a while and communication ceased. they did send LOD at that time, but i ignored it due to financial issue.

few days ago i checked my old email and realized they have been serving legal letters to a wrong address due typo for the last few years. interest and legal fees over the last 4 years of failed services amounted to 3k.

the thing is, i dont wanna waste time finding a lawyer to dispute that 3k.

i did contact the law firm that address is wrong due typo (earlier letters were served to the correct address), and that i offered to pay the original debt less the interest and fees from the years of failed services.

they have the audacity to insist that they didnt get the address wrong despite me screenshotting the legal letters and sending it to them.

so to save time and energy, im just gonna pay the full amount.

what i want to know is, how should i seek grievance?

i know im supposed to contact their DPO first before reporting to pdpc, but is this really a pdpa breach? my name, nric, address and debts are all displayed in the legal letters, and they have disputed my claim that my address is wrong 3 times in writing via separate email.

can i also report to any law agencies regarding their standard? i checked lawsoc and it says i need to be a client before i can report them.

TLDR version: law firm sent letter of demand, judgement letter and statutory demand to a wrong address due typo and refuse to admit it despite clear evidence. where and how can i report them?