Sight.... I don't want a refund I want it to work

I tried what you suggested and nothing worked. I just don't understand it, I installed it on my phone and it works perfectly but the tablet still says the same license thing. I don't have an AV or firewall installed, not that I personally installed, is there one that comes with the tablet that I don't know about?
in the anti virus avast on my laptop, I made exclusions for calibre and marked the whole folder. the windows firewall asked for permission the first time and I clicked yes and checked that its actually there. I just don't understand this.
will it help if I contact google play support? maybe they can do something? idk how this works, is this problem from the app or from google play or from my own tablet... just really sad