Serpentine belt, transmission fluid question

I am still left wondering how to find out what maintenance needs to be done what fair charges are for labor and parts.

The reason I didn’t jump to have the serpentine belt changed is because according to Toyota’s maintenance schedule, the belt initially gets inspected at 60,000 miles. They claim that they removed the belt at 39,000 miles and less than 4 years old, to inspect it (no charge), found it was cracked and needed to be replaced and put it back on. They took the belt off again (no charge) at 46,500 miles and 4 years old and said again that it had cracks and should be replaced. Again they put the belt back on. I took the car to another mechanic who told me that the belt looked fine…no cracks. It didn’t look cracked to me but I don’t really know what I am looking for. I am just trying to avoid replacing it if I don’t really need to. Money doesn’t grow on trees where I live:)

What does “servicing the transmission mean”? Flush & fill or drain & fill?