Wellindal - No product delivered -no refund - only lies

I ordered an oven on the 12th of December. They took the money from the account the same day. Never got my delivery or explanation why. I asked them and they promised me to refund me immediatly. That was on 3th of January. The past weeks they are promising me every week that the money is coming. Untill yesterday still nothing. They give a new excuse every week. But still no money after almost 2 months.
Every week another lie and promise that they are doing the best they can to refund me. What is the problem? If they can take the money why not just give it back if you cannot deliver the product. They started out by sagging that the oven was late because of the holidays ( order places on 12th December) than it would arrive the 29th. Than the product was not available anymore and they gave me the option to choose another oven that was at least 50 euro more expensive. I also could choose a refund wich I did on the 3th of January. Every since that day they lie about my refund.