Bad design, Bad customer service

The slip in vellies cannot fit although it's my size UK6. The joint by instep is too tight. I suggested that they put in an elastic band by the joint, similar to Chelsea boots. She said I must go look at their Chelsea boot on their website and order that. I don't want to buy another shoe by them. I want a refund. She said then I must return it at MY expense!! Because it's not their fault?! I said it IS their fault that the slip in vellies is badly designed and badly made as well. The stitching is ugly and the sole at the back has a terrible slant! She ignored this comment. I phoned in and she let her partner/ brother answer phone. He said the same ridiculous speech that they cannot refund me and I must buy another shoe or return my shoe at my expense! I told him that they were in the wrong and they have a terrible customer service policy on returns and accepting that the fault is in their design. So be warned, these are 'tryers' who do not accept responsibility for a badly made shoe!