Cannot arrange collection and a refund for an online order

Builders Warehouse website is terribly designed with a bad user experience in general, but the inability to submit a complaint via their Contact Us section is the worst part, coupled with a major waiting period when trying to call them and their Live chat option is also not functional. I ordered 130 boxes of floor tiles online that arrived looking vastly different to the batch I saw on display. Its close to impossible to get any help to arrange collection and a refund.