1. In UAE, living here I have heard from trustworthy individuals that there is a doubt on the authenticity of the Halal stamp on Food. Why cant the halal food stamp be trusted?

2. Secondly, if food is ordered – by mistake – from a restaurant that also serves alcohol (Muslim country), can it be consumed?

1. It is up to you to investigate
2. Yes though it is not permissible to consume where alcohol is being served, so if it is taken away from the premises it would be fine