Those were some hardcore roaches if they were texting you. You should have called the police.
Seriously, though, if your condition were that severe, you wouldn't have been able to stay there 10% of the time.
I'm not a host, I'm a guest who has 25 of years of customer service work experience at every level as well as a finely honed detector for manipulation. It sounds to me like you're trying to get a free stay after the fact. I would have to see the pictures (and the texts from those little terrorists) before making a judgment call, but this has set off my detector so hard, I wouldn't be surprised if you brought the roaches with you and planted them, or at the best, that you didn't bring them and oh my god, there were one or two roaches when some food got left out, let's capitalize on that. If it was really that bad, by all means, quit brandishing threats and go for the legal action. It's a very old scam to go to a fancy restaurant, eat most of a fine meal, drop a roach in the food, complain loudly, and threaten a lawsuit.
You have no previous reviews, the host took a chance on you, and now you'll likely pull the entitlement/scam card and either write a false review or blow tiny things way out of proportion because the host didn't cave to your threats and give you a freebie. I'll need to set myself a reminder and watch your profile for the host review and then see how you reviewed them. I've got the popcorn ready, I'm expecting quite a show. I really hope I'm wrong, because it's honestly sad to see people treat each other this way.
P.S. I hope you changed your number. Roaches are the worst. They'll give out your number to all their friends and blow your phone up day and night, but especially at night.