SUPERSONIC THE WORST ISP EVER

I got fibre installed with Vumatel 3 weeks ago and Supersonic as the ISP , i took a 20mbps fibre line since day 1 , i have been having issues getting speed at below 1mbps, i have called them over 30 times since and they just tell me the problem as been escalated i cannot stream or anything, they have been trying to make it seem like there is an installation issue but the speed seems perfect very late at night and early in the morning nobody seems to want to help,i sent the email with all the speed tests and tried everything that they have told me to do ,i did send the email to cancel the line and they tell me i need to wait a calender month for cancellation which is the end of June ,i have paid the upfront fee to get the line installed, i do not care anymore if its a loss, i just need my line freed and canceled from them immediately so i can change ISP, please if somebody knows what i can do please assit, i cannot get hold of vumatel they now say i must contact Supersonic which is a waste of time