"Your have reach your credit limit" a system generated issue

Lately I have been experiencing, "reaching my credit limit " by the beginning of each month and my lines get interrupted /cut off...when you phone the call centre the agents also seem to be confused because I'm in my credit limit...however it is apparently a device obligation fee that's triggering the system due to an early upgrade...which is already included in the bill...but some how the system is generating this amount again or should I say duplicating it which make the credit limit go more than it should....now what I don't understand is why dont they rectify this error on the system....one consultant even told me to pay in this certain amount at checkers/shoprite to stop triggering the system...to my surprise by the end of the month...this exact amount was deducted from the normal statement....so why the hell is this amount triggering my account to be suspended if it's in Reality like a fantasy amount....telkom is giving unnecessary stress...the end of the day I have 6 lines ,what if I decide not to pay anymore, than you have a valid reason to cut the lines....please let me not go this way....I need people higher than call center agents to assist me or I will not pay any more , R4000 a month...telkom is honestly ****ing me off cos this is not a real amount but a system error...