Harassment from RCS

Absolutely disgusting service. Ive had this account for years and never skipped or missed a payment. I pay my account via their website www.rcs.co.za. This month of Feb I paid online again but they can't allocate my payment. Ive sent them more than 30 emails from 2 email addresses with the correct account number but they still not allocating my payment. I spend hours and days on the phone, im wasting my time and money calling. Im very angry, if they have payment options why can't they be able to allocate the payment. How many times must I send through the proof of payment to ***.