Failing to Debit Correctly

Last year i joined Vodacom taking a S4 everything was running smoothly until November last year where my debit had fallen on a weekend , which failed to debit my account i then got a phone call from vodacom saying my account was in arrears and needed to be corrected. we then set up another debit date for the amount to go off. i the received another phone call saying the debit had not gone off due to insufficient funds. i then checked my bank statements for that week and had seen there was more than enough money for the debit. they had then handed me over to Jacobs Bernard and associates where a payment plan was made and i was blacklisted, and all this not because of me but vodacoms incompetence to debit. but still i was not bothered i went on trying to get it resolved. today i then get another call from Jacobs Bernard and associates saying i have not made one payment since February and i must now pay a total of R3919.94 as a lump sum. which i am definitely not pleased about. i am tried first to be okay and help but now i am just furious and really unhappy with vodacoms service and customer relationship skills. Ive been trying to see someone and get this resolved.