Bettas are piggies once they are adjusted to their new homes. Sometimes it can take weeks for them to fully adjust and be comfortable enough to eat healthy. And sometimes you get ones that have no trouble eating right away. I have had a mix of both myself. Every type of food, I've tried. New Life Spectrum is a good brand to get, as most picky eaters will prefer those pellets over any others.
They won't allow themselves to starve to death (unless they are ill), so continue attempting to feed twice a day, eventually they will learn that they are only going to have what is given to them and will eat.
Breeders feed specific foods while they are young, then days to a week or so prior to shipping, they are not fed usually. And it's a toss up if they are fed while in the cups at the stores- a lot of stores won't feed them, or feed them very very little as to not dirty up the cups too much with left over food and waste.
So sometimes you are having to get them back into the habit of eating, and eating what you are offering.. add that on top of the stress of the move and into a larger home when they are used to jars and cups- that's a lot to adjust to.
I have one that has been with me for a month, and he still won't eat regularly. In fact, he refuses to eat the food until it has sunk to the bottom and softened up. I don't like doing that, as the longer the food sits in the water, the less nutrition it has, as it starts to lose it's nutritional value the minute it hits the water. But there is nothing I can do about it, just the way he is.
So don't get too worried just yet, they will eat when they are ready and it takes weeks to a month before they starve.