Iam being **********

I am furious as this company is ripping me off. I bought a phone on contract December and it was R225 and was told it will go up if i want it to be a top up to R260 and i accepted. January they deducted R400 n odd, Feb R360 odd March same amount and April. I keep going there saying they will sort it out but till today nothing has been done. What are my rights as a customer being ********** by a big company.