What can a debt collector do to tourist living outside usa

by Khaled
(Cairo, Egypt)

Dear sir
I am a tourist that visited usa and rented a car and i got into car accident, i paid my insurance but i want to know what to do if i got followed by a debt collector while am not living in usa and am not a citizen of USA. will i be able to enter USA again as a tourist or i will be arrested. and what shall i do if i received a letter from a debt collector and i didn't response

Thanks and best regards