I’m sorry to hear that, but cooking can have unexpected outcomes sometimes even if you’re a seasoned chef. That being said maybe consider the following and try it again:

I’ve found that if you don’t use enough braising liquid your meat can come out a bit tough. I usually use just enough to cover the ingredients with maybe a few spots sticking out above the liquid.

Also, if you’re putting the stew in the oven with the lid on your meat will cook faster since there is no cooling from evaporation. You could try leaving the lid 90% of the way on so some steam can escape and your sauce can reduce.

Lastly, make sure the meat is cut into about 2 inch chunks. All meat shrinks up when it cooks and larger chunks cook slower and retain their structure/texture better. They are also more resistant to overcooking so you can have some leeway if you accidentally leave it in too long. Once you can cut a beef chunk in half with a fork it’s done!

Sorry for the novel, but I sincerely hope this helps you out in the future!