loot incorrect refund

On the 6th June 2020 I purchased 2 consecutive series of Downton Abbey (series 5 (R240)and 6 (R179)) from Loot. I paid using a Discovery voucher (which can only be redeemed once) and the balance I paid on my credit card. A few days later I received a mail to say that series 5 is no longer available and they have refunded me but have shipped series 6. I rep**** that I no longer want series 6 if series 5 is not available and would rather have a refund for the full deal. It is very evident that my emails to loot are not being read and every reply I receive from them is we are sorry for the disppointment. They have refunded R169 to my credit card sand said the balance has been refunded to the Discovery voucher - which I have explained innumerous emails that I cannot access as Discovery vouchers can only be redeemed once. They advertised a product which I paid for in full, it is no longer available and I have only been partially refunded. They do not acknowledge this at all but want me to rate if my problem has been sorted when I say no they either do not reply or say we are sorry for the disappointment. Furthermore I would never have ordered series 6 if I did not have series 5 and did indicate this but they still sent series 6 without reading my mail. When I try to contact loot telephonically the answering service says that due to COVID 19 they are not taking telephone calls and all matters must be dealt with via email but they are not reading the emails. I am therefore unable to take this matter further.