To add to that, as a foreigner you don't even have a right to an attorney as long as they do not arrest you.

So yes they can just send you back, it is in their capabilities and there's nothing the foreigner can do to counter that decision.

Of course not. Every country has the right to determine who is admissible. There is no right to enter a country where you're not a citizen.

Yes, but the whole point of the attorney is to make sure that the correct laws are applied to you. This ensures that it's the country that's determining who is admissible rather than just a petty tyrant who got out on the wrong side of the bed.

But you're not under arrest or being detailed in this case. Not sure what a lawyer could do in this instance.