I have been struggling for 3 months with my wifi I made numerous calls ,send emails I logged calls

I have been struggling for 3 months with my wifi I made numerous calls ,send emails I logged calls .the last time I spoke to a operator she told me they wil send me a new router yesterday...as usual nothing happened. I have wifi for maybe 3 min then it's gone for like 7-8 minutes ongoing for the past 3 months. I never complain about my payments but there is no use for me paying for something I can't use.i work from home and it's affecting my work.but eversince day 1 I had a problem when they brought my Sim they never gave me a router I waited for 8 months until I went to fetch it myself in Durban wile I was on holiday. I logged a call back on yesterday morning up until now nobody called me back.and if I cancel my wifi I wil not pay them a single sent because for 3 months I hardly used their wifi due to lack of network