Unauthorized upgrade

Vodacom service is so poor, how l regret using them, to cut long story short, 2017 l took a cotract wth them, they gave me a line that belonged to somebody, and wen they realised that, they jus disconnected me, so ended up given a new line, not that l had a choice as they put it, l took a new line which they wanted me to pay fo it and l refused and so they gave me finally, then last year l phoned them for a settlement to cancel my contract, a lady by the name, Nongqayi or Noncayi called me, and apologised bla bla and she offered me data abt 5gb day and 5gb nyt, to my surprise this yer because l knew that my contracts are expiring, l called them only to find out that this lady actually did an upgrade on my data contract, which l was not aware and didnt authorise, so l spoke to various consultants thru the cancelation department, including a supervisor called Louisa, she promised to find out, retrieve the the call that l had wth the lady that upgraded my contract, till today, everytym l fone nw they say she is not in her desk, l spok to another guy who tried to help me, he also has given up, unfortunately wen u ask them wher yu can walk in and make a complain they say ther is no such yu can only make a call, l sent an email, got a response that a consultant wil call me in 24hrs,tday its the 5th day, noone has called, they are so a pain in the neck, l think lm resorting in stopping the debit, a big company like vodacom very ***********, *****