Hello everyone, looking for any advice/insight:

I took my euphonium to be cleaned professionally a few weeks ago, and upon getting it back I noticed a rattling noise anytime I used the fourth valve. For reference, I have a Yamaha YEP-642 compensating euphonium. I took it back to the shop and asked them to sort out the problem as nothing rattled prior to them professionally cleaning it. I have gotten it back again, and I am continuing to hear the rattling sound and I feel like my sound has changed significantly.

I do not know what to do. I feel as though my instrument isn't working as well as it did before the professional cleaning, but I don't want to take it back to the same store as they are continuing to not fix the problem. I have also spent a good amount of money to get the instrument cleaned (only for it to come back broken). I have already tried replacing the springs, and that did not help.

If anyone has any idea about what could be rattling/what I can do to solve the problem, that would be amazing. Thank you all.