Worst and terrible service and I want my money back.

I got a Sim Card Only contract for 25G per month with Afrihost and they also advised on which mobile/portable router is compatible with the Sim Card. They offered a free 25G for the first month and could not use it due to poor coverage. I contacted Afrihost to cancel the contract within a week of receiving the Sim Card but they never cancelled the contract because they deducted my account on the 3rd September 2018. This the worst and terrible company to work with because I have never used their free data but they still do the deduction.