Taking more than they should

yesterday my account has been deducted from the debit order but yet again for the 3rd time now they have taken more than they should, my general account is R749 but yet every month they deduct more than a R1000 then i have to call in and then they cant even refund the amount the load the credit onto your account this is very poor and unacceptable i will no longer refer people to use vodacom as they ***** from people thinking they will not pick it up i manage my accounts so i know where every cent goes. i wonder what excuse they will have i will share this report on all social media as this is unacceptable