Refund for goods not received.

I ordered a lawnmower from Mr Shopper online on the 4th December 2020. As yet I have not received it and requested a refund. I am unable to get hold of them by telephone , or email or on their website. I would really appreciate a refund in my bank account by this week or I will contact the Consumer Goods & Services Ombud and lay a complaint against them. Thank you.