RCS have too many clients, dont expect service.

I took out a loan last year and for the past 2 months I have been trying to settle this loan. I have contacted them, I have sent numerous emails and I did receive confirmation that they received the emails and will get back to me within 24 to 48 hours but to date, I am still battling. I decided to cancel my debit order and to pay 98% of the account until I receive a new statement. Up to date this payment does not reflect on my statement. I got a message saying I am still owing money which I paid immediately and I sent the proof of payment. I have been receiving threatening emails and calls from debt collectors about this account. Terrible terrible service.