REFUSED to acknowledge consumer rights

I ordered one of the collars for our dog, but befire it arrived we realised it’s not how we needed to train our rescue who is v sensitive. We didn’t open the product at all and promortly repackaged it to get it sent back with in their strict 1 week refund policy. Sent it recorded and signed for. The first delivery attempt- no one in. Rebooked it for the following week. THEY REFUSED the parcel. That’s the reason Royal Mail gave me. They refused it- so no delivery to them no refund.
Also during that week I tried to make contact with people from the company to ask the refund process and explain we were returning it unopened. Barely got two sentences back and no help.
They do not allow you to exercise your consumer rights. I will be copying and pasting this review everywhere