I've seen that a lot on 99 buck android tablets. They usually work but there is no support. If they break, you find no warranty either. I see you returned them so at least you got out fast.
I bought (3) of the Black Friday 10" Polaroid tablets from Menards. I only opened one - I could surf, check email, download apps, read books on Kindle for Android. Now the wk before Xmas it went to hell. Tried to master reset and made no difference. Their 'Support' is basically non-existant. My sons have now opened their tablets for Christmas and are now all (3) having the same issues. Can't get past 1st page when going online. Can't download any AppStores. Any of the pre-installed apps don't work or can't get online. I have wi-fi signal. I run my laptop 24/7 on it. I've changed the channel on my wireless router and still no difference. Anyone have ANY advice? I'm ready to return all 3 and buy Kindle Paperwhites (all I can afford) but really wanted to have apps, etc.