Mtn bad service provider

I had bad exprience with MTN i took a router contract with them 24 months R289 in December 2018 first debit order was right in January from February till this month they have been taking more than we agreed on R500 or R400 last month i went into the store it was the 23rd March i was helped by a lady called Palesa she told she can't do much cause their system its slow she took my details and said she will come back to me regarding my problem she never came back to me so yesterday to be precisely on the 3rd of this month I went back there to ask about my inquiry they did nothing about it I was told again they will call their head office to fix the matter so im still waiting for their respond Lastly there lady by the name of Lindiwe she's so unprofessional she doesnt even make eye contact when the clients greet her what made me angry she was chewing a gum in a work place that is so unacceptable behaviour