Origination of our infestation

I’ll start from the beginning… we stopped at a pet friendly hotel off a highway. We walked in the room and were met with a very strong wet smell. The air conditioner was on full blast, and after a few minutes we realized the carpet was soaked. A few minutes later, we realized there were fleas crawling allllll over the dog, specifically his paws and legs. We left immediately and drove the last 5 hours of our trip. Upon arrival I combed the dog out, gave him a dish detergent bath, and found about 10 fleas, but no more. 
Called the vet and they said to give his monthly med some time to kill the fleas on him. We didn’t see any more fleas for 5 more days. 5 days later we drove back home and found fleas on him while in the car. Did the same bath, etc when we got home, assumed a few stragglers had been in his dog bed. 
Cut to one week later and I’m still finding them–the vet immediately says to get the house treated. Exterminators find fleas. Not very many, but they are present in the enviornment. After two treatments and no sight of fleas in over a week, they say I’m probably in the clear (though I’ll continue vacuuming etc). 
Question is.. is it possible that it took about 2 weeks for them to transfer into my apartment? Or is it more likely they were here to begin with? Worth noting we never saw them prior to the hotel, and never had gotten bitten ourselves prior to hotel. The most likely answer is pretty important before I try showing them my treatment bills for reimbursement (they already refunded my stay and did not argue fleas).