Contract Canceletion

So my services were terminated because we did top up on my WiFi and we didn't know that we had to pay immediately we thought they deduct the money with monthly installment, my issue here is i have requested fiber 2 weeks ago and i was fully installed and everything was fine until they cancel my services i mean i did not do the top up on my fiber why cancel it ? i tried calling asking them to reinstate it but they refuse, why would you give someone fiber for 2 weeks then later cancel it? and on top of that they want me to pay the cancellation fee.. i'm not going to pay any cancellation fee coz i still need the WiFi its either they reinstate my service or not charge me at all