Quick mobile fix is a scam. Quick mobile fix is a fraud. Do not give them any of your business unless you want a big headache to get your money back. Don't just take my word for it, check out the independent reviews or facebook pages. There are many people out there. This company appears to be a deliberate fraud. I really suspect the Trust Pilot reviews. Their accounts on companies house are not audited. Ordered a phone. No phone delivered. No refund despite numerous emails. Phone calls don't work.
If you are in this unfortunate situation, then get in touch with your bank / credit card company for a refund through a system called charge back, but this must be done within 120 days of purchase. It appears this company uses any excuse to avoid its responsibilities and will try to extend their protracted lack of action to beyond the 120 day limit.
Also report them to the Redbridge Trading Standards. Why trading standards allows them to continue trading I don't know.
We have written many emails and get standard replies. They are using covid as an excuse.
If your bank can't or won't help, then your next option will be to take them to the small claims court.