One day only shocker

OneDayOnly have now reneged three times on a faulty item purchased in April. I ordered 2 Aeon hand held vacuum cleaners, one worked and one didn’t. I returned one, they returned it back saying it was fixed. Lo and behold, looked like never touched nor opened. Did exact same thing. They told me to repack and they will collect and wait for supplier to advise . It is now a month and they ignoring every email (daily sent) parcel waiting amd now want a full refund. Cannot reach anyone to help ..please ad use