Dirty underhanded tactics on Refund

I made a purchase from Leroy Merlin using Payflex Their technician confirmed the door was not suitable for the garage and I must return it for a refund.,For the refund Leroy insists that Payflex refunded last year. Payflex is giving clear explanations of the amount they refunded to Leroy but Leroy is playing dirty tricks insisting that Payflex has already refunded into my account and they want me to send my bank statement so that they can go through the transactions in my account and determine that the money was not deposited. They wont check the proof of payment nor liaise with Payflex. Payflex has even sent me emails to say the refund is on its way from Leroy !

I did not expect such stickiness from Leroy. Now they keep sending emails to say the matter was resolved.