27th March furniture was delivered and we'd paid f...

27th March furniture was delivered and we'd paid for installation. They didn't install it. Over 10 weeks later, four phones call (half an hour on hold minimum each time), and each time they assure us that we'll have a refund of the installation within 4-5 working days. Nothing. Now we phone and there's just voicemail. We followed each phone call up with an email confirming what was agreed, all read receipted, and they delete them without reading. We don't believe they have ANY intention of refunding the installation fee.