Southwest FL Rental has ANTS!! Help!

[Chelsea John-Williams]

I have a rental home in southwest Florida. The tenant recently called and said he had an ant problem that he tried to take care of by himself but was unsuccessful. I went to the property and sprayed for ants inside as well as outside. Now they're dying inside the home in piles. The fact that they're dying is a good thing but he is claiming that he cleans them up and more ants are found dead in the same spot hours later. Pest control companies are extremely expensive. Any suggestions?