BE careful, you will NEVER get your refund back

I cancelled my 5G contract within a period that entitled me to a full refund. The device was delivered on the 5th of Jan and I had to cancel the contract due to connectivity issues. The device was collected on the 6th of Jan, but they are refusing to refund my account. I have confirmed with the courier company they sent to collect that the device has been delivered to them but still RAIN refuses to refund me