Vodacom Black Friday ****

I took out a vodacom uncapped wifi deal on black Friday. 5 months down the line, they decide that they are changing this contract to a capped wifi contract. I was not aware of this change until the streaming in my house became so slow that I could not use any of it anymore. I then phoned Vodacom (***) on 25 April to ask if I can cancel this contract, I got a quotation for R7324.56. I left it for another month and went back to vodacom Riverside to ask why the wifi has become so slow. They then informed me that because vodacom changed this contract, users had the opportunity to cancel their contracts until end of April free of charge. Why was I then sent a quotation when my request to cancel was within this free cancellation period? Reference for quotation *** I then submitted a service request to cancel my contract and another email, but I am getting no response.