Help With Seamaster 300M

Last year around this time I bought a pre-owned 212.30.41.20.03.001 from a respectable jeweler online. The original purchase less than a month prior, so it has box and papers with plenty of factory warranty left. Sometime during the summer I noticed a sound coming from the watch that sounded like the mainspring sliding around in the barrell. I wear the watch almost everyday and there is there is no way I am getting close to the power running out. It had been keeping good time but I was concerned with the noise, so I took it to an Omega boutique near me. They sent it away and the service center said there was a winding issue. It was returned 6 weeks later. About 6 weeks later I heard the noise again, recorded it on my phone, and took it back. The service center said there was a winding issue again and returned it this weekend. I've had the watch back for 5 days and I heard the noise again.

I'm losing faith in the services center's ability to fix the problem but don't want to pay to have it fixed. I'm at a loss on hoe to proceed and need some guidance.

Hearin the slide during normal use, in the evening, after a day of wearing the watch.

The impression I get rom the noise is that the mainspring is unwound to the point where it is loose and can move around a bit. I wear the watch all the time and the mainspring should be wound, particularly in the evening (when I hear the noise) after a day of wearing it and moving around.

EDIT: Also, the date wheel doesn't full flip some days.

Im sure it is the ball bearing that you hear while the rotor is moving as its on your wrist. Im curious about the service center its going to because the work performed that you are stating sounds odd being the results you have now.