No one assists but when they want the money they can call 10 thousand times

They do not locate cash payments made if not a debit order & it affects my credit score, I then paid in full no paid-up letter trying to get someone to assist no one responds to e-mails call the call center it cuts after a while I hold on for hours This is affecting my credit and I need to apply for stuff that is causing an issue. I was paying Jet before and no record as well of my payment under my name how can an eft payment not be allocated but we pay?