DONT OPEN QUEENSPARK ACCOUNT EVER!!!

My account was paid in full with 0 rand balance for many months. Then on 9 SEP I bought for an amount of R869. Three weeks later I pay almost the entire amount R795.00 ,which means I paid a couple of months installments in advance.To my surprise I got a Sms beginning Nov stating I am in arrears and must payR80.I did not pay as I paid already almost full amount.I sent a mail asking about this and was informed its costs.I sent a reply asking for statements and a breakdown of the extra amount.While waiting and not getting a reply I got another sms staing I need to pay R98 immediately. I phoned asking why if I did pay a few months payment in advance but was told I now need to pay R117.39.as they add costs for every sms and mail.Why cant the system calculate the payments and allocate it to the next couple of months installments???So Im getting penalized for being a GOOD payer