Need Advice about a Tonbux Tablet

[BallyS]

HI

I recently got this Tablet and it is full of Advertising and stuff, and would like to clear it off by maybe putting a different ROM software?

The only info I could get is this

Model GT90H
Dual Core A23
Android Version 4.4.2
Build Number
polaris p1-eng 4.4.2 kvt49l 20140808 test-keys

The Chip inside says All Winner and Motherboard has
gt90h v1.4 2014 07 25


Any idea what I could do with this?