UNKNOWN PAYMENT

I have taken out a contract with Telkom in June ..It was a galaxy a8 phone and it was R199 for 36 months 10gb The sales consultant said it can be done with 24 months so I said its okay.I then later discovered on the invoice that it was not the amount that we agreed on. Then I went to the store to query it, they said they will attend to the matter. They created a reference number then later it was closed saying it was resolved. I called Telkom they created another reference then it was closed AGAIN...I sent them numerous inbox messages on FACEBOOK AND AGAIN REFERENCE NUMBER CREATED THEN CLOSED..Then they said I upgraded from a 10gb to a 20gb and of which I did no do such.