Dentist Fail Turns Into Farmers Market Win

I was scheduled for a teeth cleaning today, but when I came to my dentist office, there was an issue with my insurance;
Doctor: There’s an issue with your insurance
Me: What do you mean?
Dr: We can’t see you on our list, did you change it since last time you were here?
Me: Nope, still the same. Here’s my card, it even has Your name on it.
Dr: Let’s call them to see whats up
The receptionist call the insurance company who inform her that my insurance was terminated on April 1st. 
Me: But I’ve been here since
Receptionist: Yeah, I can see in our records that you were here on May 27th
Me: It says here on the card “Effective from March 1st” and “Card Issue Date March 15th”, why would they terminate my insurance on April 1st?
Receptionist got connected to someone else and put on hold for 50 (fifty!!) minutes, pushing 6pm, before I gave up and said “listen, I’ll call them tomorrow and then we’ll set up a new time for my cleaning”.
I thought about it for a while, I have everything on auto-pay and had, to be honest no clue if I had paid or not, but I had a doctors visit back in July and the health insurance worked all dandy back then so it’s a little odd. And how was my dentist visit in May covered if my dental insurance was terminated on April 1st? 
I didn’t really feel like I had to have my teeth cleaned again, so I was not so upset about the whole thing, more than I just wish a lot of things would run much smoother in this country and that I had made a point to take the evening off work to go to the dentist.
I used to get home from work early every day, but that was months ago now so I had almost forgotten what it was like. Driving back from the dentist I realized it’s Tuesday and Tuesday means Farmers Market in Culver City, WIN!