Rain still charge you when you canceled your data simkaart.

I had Rain uncapped wifi that works with a simkaart for a few months and then I decided to get other fibre internet.How it works you pay first and then you get your data.I phone them a month before I canceled my Rain internet to let them know I'm canceling Rain.And the ppl still phone me to pay my account.When you don't pay you don't get your data on your Sim right.I check on their site and they saying my account is behind with almost 2000.How do you get to this amount.I did phone to cancel it and I did send an email. YOU DONT SIGN A CONTRACT WITH RAIN,IF YOU DONT PAY YOU DONT GET YOUR WIFI DATA.HOW CAN YOU STILL WANT ME TO PAY FOR SOMETHING THAT I DONT USE ANYMORE.