I had some friend with mobile devices check out my shop., no mobile devices here either.
They said it's all fine.
Supadupa did some revamping about this time last year to update for mobile devices. During that time, I was unable to upload pictures form my desk top, but had to use my laptop.
Thankfully, as they promised, they got that fixed.
You could send a copy of the Google notice to Supa support and see what they say.