There is a simple element of law that is perfect for you;

when you seek an abatement contractor; you need to have
a WRITTEN AGREEMENT that states, they agree that when
they are done with whatever they are going to do, your house
will ‘read’ asbestos free–not 5% or 1% BUT ZERO.

YOU put their fee into escrow— and until their work is tested
by an outside expert and is shown to be 100% clean, the
remediators are not paid!

And make sure they give you a 1 yr warranty.

cheers