Southern Pest Control

So I bought a $ 60 Groupon (value $ 300!) for a one-​time, inside/​outside pest spray from Sovereign Pest Control, which operates in Houston as Southern Pest ControI, made the appointment, sent the Groupon coupon to the office, attempted to give it to the technician, but he said he already had the number so didn’t need a copy, and three weeks later, received a bill in the mail from them for the same $ 60! I was careful to comply with the fine print, so no issues there. I sent them an email four days ago pointing all this out and have yet to receive a response.
The service technician spent not more than fifteen minutes on my property while delivering what was advertised as a $ 300 treatment. The house is a 3500 square foot, three story, free-​standing home. The technician did not enter the side yard on the north of the house. I do not believe he sprayed the front of the house or the garage perimeter. He did spend a minute or two in the side yard at the south of the house. Afterwards, we found a few dead roaches in the kitchen, and sadly a few live roaches as well.
In the meantime, i have had email exchanges with Groupon and they have issued me a partial credit.
Other than my dealings with Groupon, it was a completely unsatisfactory experience.