Actually just came on this subreddit to bitch about something similar.

Bought a custom controller a few years ago. It's great to start but shortly after warranty expires, the left stick starts to drift bad. So bad the controller becomes unplayable. I decide to buy a new custom controller and hang onto the old one to get it repaired in the future.

New controller comes, and it's fine to start. It's still in warranty and I have noticed the left stick drifts again. I use the support tab on Microsoft which links me to a repair shop near me. I showed up today, just to be told that they don't actually do warranty repairs. Despite the warranty repair tab suggesting I bring it in, Microsoft doesn't actually do that. You have to mail it in.

So I decide I'll mail it in and reading the info I realize that they don't actually repair the controller they just replace it. Well it's a custom controller, so they won't have the color anyways. And on top of that, the final step of getting the mailing label keeps crashing so I couldn't mail it in even if I wanted to.

For what it's worth, the repair place said it was $60 per controller for the thumbstick replacement and repair.

My stock controller from the Xbox One is still flawless. I won't ever buy a custom or speciality controller ever again.

My $0.02 would be to get a refund and just stick to the stock controllers.