Have you tried contacting them directly and asking??
This is not a company we see discussed here very often. Not sure why. A red flag for me? Usually a towncar company will list a free grocery stop on their website...there is nothing regarding this on the website for Florida Towncar Service. The other thing? The vast majority of car services charge around $200 for r/t to Sanford. This company charges only $120. I am a huge proponant of you get what you pay for.
Contact the company directly and see what they say about the grocery stop.