Leroy Merlin Marketplace - bad service and irritatingly slow to no communication

We purchased a stove from Leroy merlin online. The dimensions were incorrectly published so the stove was too small, we called and asked for a refund last saturday. Now. a week later and it still hasn’t been collected or refunded. What’s more, when we call Leroy Merlin they cannot get hold of the seller till Monday. Very disappointed and frustrated .