Bad service

I have registered with the institution in October and finalized my application in November. Their service was 100% I think it's all because they expected a deposit and approval of the debit order. I have paid my first deposit there's like 2 installments already debited. Sad enough even after paying on time I got messages that I will be listed into credit bureaus. This morning I got a final notice. I am so frustrated because even if I call them or email them they don't respond I have been panicking sending emails hoping to get hold of them. I wish I can just unregister with the institution because I don't what else to expect from them. I am so dissatisfied and hope to get myself out of the institution and register with a different company.