Not the speed you pay for

After only 15 days with you, I'm now fed up. My 120mbps speed that I pay for is not anywhere near that. This has been since day one. Every time it's frogfoots fault. This is pathetic. My account is paid in advance aswell for next month. Your watsapp never works. The app is a total mess, with zero reply to any technical query. If not fixed asap, I will be canceling, and seeking other isp. I will not pay any installation fees. As there was an existing frogfoot network when I moved in.