Worst service at mtn

I was at mtn Goldfields Sabc 1350 last year to apply for a contract. Im a student at Tosa Fet, I was assisted by Vuyokazi Zulu the sales consultant... I asked for a device for the amount of R300 per month.... But apparently mtn gave score of 3000 and then I was given a device for R650 per month... When I realized that the device I was being given was beyond what I had asked for, I told the lady I didn't want the expensive device cause I wouldn't be able to pay that amount... Her response was "I should sell the device and pay mtn....". I left the device with her and asked she cancel the contract as it's not what I asked for.... Till today the contract is not canceled and I still need to pay for something I didn't ask for....