nightmare from mtn

im totally disgusted with the service of mtn. after three and a half months of calling, mailing and going into there store my phone number is still blocked on the mtn network. they are now cutting my services every week as they cant allocate my payment so they suspend all my lines with out warning me. if that is not enough they want me to pay another R6500 to reconnect my lines because they say the account is 60 days behind after i just paid them in advance. im at wits end as i feel there is no way out and they simply promise to call back with no response.