Marketplace not doing their part

I am experiencing horrible service. I bought carpets on Marketplace, I need to return them however the store will not take them as they were an online deal now the process is taking forever. I have been communicating with market place team but this does not seem fruitful. The carpets are still not collected for the return process and this means I am not getting my refund. This supplier under Leroy Merlin Market Place is not efficient and this is now making my experience with Leroy Merlin.