Avoid Vumatel, very bad customer service

I cancelled my subscription with Supersonic on the Vumatel line, no hassle from Supersonic side, but Vumatel on the other hand is busy sending me back and forth saying my line is not released and asking for proof that my subscription is cancelled, Supersonic sent the proof but Vumatel keeps refusing to release my line so the new service provider can take over my subscription. I reached out to them via calling and via Facebook but I keep getting the same answer. Now I’m stuck without internet. Worse thing is that the only fibre line provider on my street is Vumatel, their customer service is pathetic.