Smytten - Not refunding money

I ordered from smytten a lip balm , but I was given a smaller size . So I asked for a replacement. They came and took the product the next day and after a few days they gave a new parcel , which again contained the smaller size of product , not the correct size which I ordered. I once again complained ,they came and took the product and told me they will refund me the money in my bank account in *-* days . It has been almost a month but I did not receive the refund . I sent countless emails. Now they are just giving me a *** rupees voucher saying it is the best they can do . Why should I incur the loss because of their carelessness? They are giving me a voucher with amount less than the one I paid , and for even using the voucher I have to use my own extra money , why would I do that ? They give fake promises they will refund money in the bank and then just give a voucher of lesser amount.