Sick VW Beatle convert

I just got my Beatle back from a 20K check up where they changed oil, flushed the brake fluid, etc. After driving 2 miles, white smoke came from both front wheel wells and it was difficult to accelerate. Are the brake calipers stuck? And if so, should I make the mechanic replace them or what should I be sure that they do to correct the problem? (I wasn’t having the problem when I brought the car in for its check up.) have they shortened the life of my brakes?

Thanks in advance for any and all advice.

It sounds like your brakes are dragging now. If they were smoking you should have the dealer replace every single part that got overheated.
I very much doubt that any of those brake parts are safe to drive with anymore.

There is a very important question here… what year?

There’s a lot of old air-cooled beetle convertables driving around with disc brakes, which are of course completely different cars from the new ones.

Oh… 20K checkup… probably new.

The car is 4 years old. I bought it new but only drive it about 5,000 miles per year. I arranged for a tow back to the dealer and when I drove it out of the garage this morning, it was fine. So does this help diagnose the problem? Now I’m afraid the dealer will say there is nothing wrong. But, I am assuming that overnight the calipers released and would lock again if I started to drive and use the brakes. Would that be a correct assumption?
thanks

There may be something wrong with the master cylinder. Maybe the bypass valve.
What likely happened is that the brakes dragged a little which made them heat up and expand and drag even more. Now they are cooled down and relatively loose.
Ironically, I had exactly the same thing happen (smoke and all) to a '64 Beetle I used to have. Once it cooled, the brakes worked again. The parts still needed to be replaced though. I had it towed too.