No support bad service

I app****, they came and installed Air fibre on Sunday,but it is not working,it kept on saying limited connection, they said it will be fine the next day only to find out it is not, you can't even call them , communication is on WhatsApp which is automated, they respond after hours and don't even give you a solution, I contacted the installers to let them know how frustrated i am,3 days later nothing is resolved but they will be payment month end,I decided they must come remove their router ill get another provider