Poor communication and customer service

I bought a Garmin watch for my wife on the 02 January 2020, through Multiply online store. They sent me the watch, and we had to return it because it was not working. They sent us a new one but also we had to sent it back because it had the same problem. Than Garmin contacted me, because it was returned twice they offered me an upgrade, of which I will had to add R2000 for the new watch. I decline and said I will request my refund. Than lockdown came. I sent a message to Multiply online shop, 17 March, and I had to confirm that the item is still with Garmin, on the 23rd March they told me they are still waiting for feedback from Garmin. On the 27th of April i sent them another message and after 2 days they came back and informed me Garmin office is still close due to the lockdown of which I understood. On the 16th of June I sent them another message , all they said was that they sent a request to Garmin Support team for further assistance. I did not find any joy of using their preferred communication channels via their website. I saw an advert on Facebook, and I took it up with them there, it move a bit faster and I got quick response. In the meantime Garmin sent me back the item and I opened the box to see whether everything is in what I sent to them. Than Multiply online sent me an email I must confirm the receipt of the item, and ask whether me about 2 times with different emails did I open the box. I explained to them why I opened it, and they informed me they will take 15% of my refund because I opened the box. I reasoned with them, that it is not that I wanted to return the item , I returned it because it was not working. After that, they said they wait now for senior management to approve the refund. I gave them time. After a few weeks I contacted them and the consultant told me he will check with finance and will come back to me. after two days I contacted them again, I was informed that finance paid but it came back from my bank because of my bank details is outdated. I could not understand because my debit order goes off every month without any problems. So I sent them my banking details. After few days I contacted them again, the consultant told me he could see that they did received my banking details. I was happy at least I will get my refund. Nothing happened, I use their WhatsApp communication, to ask what is happening with my refund, they ask me again my bank details, by this time I was really frustrated. I sent it via email, they keep on telling me they did not received it, I probably sent the same email about 5 times, than they gave me another email address, it also did not work. I think the following day they said they received all my emails, they think it was a system error on their side. Finally I got my full refund back. I made myself a promise never to buy from Multiply online store anymore. I can get products they advertise lower than with their discounts if I just search around.