Overbilled by Telkom

Yooooh I'm not happy with the billing. Initially I took out a wifi router and data deal.for 239 a month giving me 20gig day and 20gig night surfer, but this month I was ridiculously billed 703. And Gladys the lady who was helping mw with the contract was rude and didn't help me in any way instead she blocked me, I though Telekom was a.fair service provider but I'm Highly disappointed