IDA LAW HARRASSING ME EVEN THOUGH I PAY MONTHLY

I'm experiencing a serious issue with IDA Law regarding two accounts for Boodle. Despite making regular monthly payments and sending proof, I receive threatening texts claiming non-payment. One time, I used an incorrect reference for a paid account, and it was a hassle to rectify. This month, my reference was missing a digit, but they eventually allocated the payment. Yet, I'm still receiving notices saying I haven't paid. Who can I escalate this to? The treatment I'm receiving is unprofessional and frustrating.