Data prices not as per adverti*****t

Rain advertises data at R10 per gig and yet I have been paying R50.00 per gig. Either you give me the extra data TODAY or I report you for false advertising and I stop my Rain services after being with you for years. The adverti*****ts says nothing about calling Rain every time I want to buy data. I asked about fair use policies when I signed up and Rain said they dont have any