Supersonic down the drain

Been 3 months and I have about 3 to 4 hours internet a day. Useless to try and solve it via WhatsApp, as they wifi goes down, while contacting them. When I have had success, I did everything they asked me to. Reset, reconfigure, remove sim, leave router off for 5 minutes., etc. Paying for a 30 day service, and I only get about 5 days total. I am at a with end. About to cancel. About a year ago the service and reliability was excellent, now it is just plain useless.