Contact terms and conditions to be reviewed

I’m a pensioner i read the terms and conditions based on contract taken and there’s no where it states that when you are unable to pay service and keep device with you, rain will charge you for keeping the device same amount as service given. This is ridiculously,unfair. I cancelled the contract and the device was collected. Still rain debited my account. I earn government grant and how can I survive after debited with out service rendered?