Poor customer service

How do I get a refund from Smarty? On receiving my smarty sim I found that it didn’t work because of poor to no signal in my area. I reported this to smarty and they promised me a refund which has not happened and they have even charged me for another month for no service. There appears to be no way of contacting them to discuss the way they rob their customers. A dishonest not very smart mobile phone provider, best avoided.