I paid my account and I'm not in arrears

I am very furious that RCS has put my account in arrears. I ALWAYS pay my account every month via the same method of payment (eft) and have them as a beneficiary. RCS has been receiving my payments every month but in April they say i didn't pay. <br> <br> I sent proof of payment and even called in to ask for this mistake to be corrected, and one of the call centre agent confirmed that they received proof of payment and will correct the error. Now I'm getting a May statement that says my account is in arrears. I'm am not going to accept such lies and need this mistake to be rectified with immediate effect. I have attached my proof of payment AGAIN for the 8th time and don't say i haven't been communicating because i have and no one has been replying to my mails.<br> <br> I need an explanation immediately!