The poor customer service

I am beyond annoyed at the situation this iD mobile company have put me in. I cancelled my mobile phone order before the confirmation but they still processed it therefore I had to return it with MY OWN MONEY, then they took days to process to my return and I STILL have NOT received my refund of £49.99 even though an agent I spoke to said it would take 3-5 days to come through it’s been over that amount of time. The customer service is USELESS they take forever to respond and are extremely unhelpful, moreover they have continued my plan which I have clarified I want to cancel. They have brought nothing but stress on to my life and I need immediate help.