Telkom taking me for a ride

Took out a p10lite cellphone deal via online options. Telkom called me back to confirm my order and offered me a modem plus data at an extra R100 a month. I agreed. My modem was delivered but telkom knows nothing about my cellphone. After probably 30 calls and requests from telkom to help fix my situation i have got no help. I ended up with a modem that i had no use for considering i got it as an add on to my phone deal. After giving up trying to get my p10lite i decided to make use of the modem since i was paying for it. Telkom then decides to bill me R580 via debit order last month instead of the usual R100. I am so frustrated at the service and total disregard that telkom has shown me. Every person i spoke to at telkom has turned out to just be a pacifier.. I am a student and this 500 rand extra that telkom has taken from me may seem like small change to them but it's a huge amount for me. I am currently writing exams and will now have to borrow money to get to campus. Thanks telkom for showing me that I'm not a valued customer..