Telkom has bad bad bad services,

I have app**** for a 10meg dsl line. Telkom installed it on the 13th Oct 2017. I got 600mbps speed for 2 days, which after then never worked. On the 15th I logged a fault and and never saw any technician nor any corrospondance from Telkom. On the 27th I got my Telkom account and said I must pay them R 2,500.00 for my line and internet. I logged a complaint as well sent my cancellation request to Telkom. However today on the 30th a technician came out and he called me before going into my premises. His name was Russel. However he confirmed to me that I only have a 2meg installed and the fastest I can get is only 4 meg... This is totally insane as I was billed for 2 months already, and never ever actually used the line nor Telkom technicians came out in more than 2 weeks, and Telkom have a deposit of R 700 of mine. According to the consumer act Telkom has breach our contract on a few ways and now I need to pay. I wont as Telkom billed me for totally the wrong service