You can’t make them taller. Can you use them somewhere else? A patio area perhaps?

Many stool designs are offered in both counter-height and bar height—perhaps you can return them for identical bar height models? Assuming that's a bar-height (42" tall) area you're wanting to sit at, you want stools whose seat is ~30" off the ground. Here's something similar.

Your wife and my husband would make quite a pair! We ordered counter height chairs, received bar height by accident, and he wanted to keep them. Thought they worked just fine. We were all bending over to eat for a month because he was being stubborn. Replace with the right height chair and use these elsewhere if you can’t replace with the same style in a taller version. Your shoulders will be much happier.