YOCO blames me because their device/system doesn't work

Recently, I had a stand at ComicCon and was using YOCO as I have been for the past 4 years. On the second day, when I needed the second machine, I turned it on well before the event started to make sure that everything worked as it's supposed to, where it promptly took 6 hours to try and update my product list, well into expo time. I contacted support to try and resolve the issue, and the AI bot was able to help me. However, I did ask to be put in contact with a human tech support to ask if they've resolved this issue on their side and if it is worth continuing to do business with YOCO, as I've had the same issue multiple times across multiple devices. Instead of answering my question, the tech support rep tried to address the individual device. This back and forth continued for three days, until another tech support told me that I should turn off the product feature on my device, as I have no products listed on my YOCO. At the time, I had 92 products, excluding variations, listed on YOCO, several of which I've had for 4 years.

So I went from a barely functioning device, to fighting with tech support to get answers, to being blamed because YOCO's systems and/or devices are not functioning as advertised.

I am actively looking for a replacement service as I cannot continue to lose business because of this.