Rain refusing to cancel service and charging me

Received my rain router on the 27th of May and cancelled it on the 4th of June and havnt uses it since.

I've called Rain several times to come pick up their router and have email proof of cancellation and a reference number.

On the 10th of October they call me for the first time and tell me that I have accumulated a R2800 bill.

I told the agent that I wasnt going to pay it and that they could come pick up the router.

He rudely told me that if I didnt pay they wouldnt pick up the router and refused to help me further.