Debit at all costs even if notice given before month end!!

I had a fiber line with Afrihost and had no issues as their service was exceptional. The contract was a month to month contract but when i called to notify them that I am cancelling my subscription because I was relocating I was told that I will still be debited the full amount for the next month because I didn't cancel before the 22nd of the month. When I stated that the contract i signed was a month to month and had no date stipulation I was told that I was supposed to check the clientzone or mobile app as that is where the date stipulation is. This is just disappointing for a company of such a magnitude and that amount debited has lost them a client for good!!!!