Bad service, no refund

I ordered a lawn mower on line, when I phoned to ask when they were going to deliver I was told they had no stock, I cancelled the order and requested a refund, this was 26 January, after numerous telephone calls and mails I am still waiting for my refund. Each time they promise to get back and they don't. I have to send new documents each time as well. I was told last week 3-5 days and I would get my refund. When I phoned again today I was asked again for new documents and told 10 days for my refund. This is beyond ***********! I am disappointed and disgusted with this tree