After months of followup involving more calls & emails than I care to count, I finally got the email this morning that I have been upgraded back to Silver.
Their excuses kept changing & something new kept coming up every time I would call.
United first said I had to wait till March 5th since that is when Marriott would renew my status. I showed them I had Lifetime Titanium status with Marriott so I didn't have to rely on a renewal every year but that made no difference as they still asked me to wait.
Then after March 5th they said they were still waiting on a confirmation from Marriott regarding my status.
A couple of phone calls later they changed their stance to the fact that I had another account with Marriott & a difference Bonvoy number was linked to my account & that was the reason my status had not been upgraded. I tried to explain that I had no other number & had been getting UA Silver through this program ever since it started years ago. I had not made any change & my Bonvoy number remained the same but that made no difference to them. They would not give me this 'different' Bonvoy number & told me I had to get in touch with Marriott to get this mystery number unlinked.
Marriott of course insisted there was no other number, my accounts were linked correctly & this was a known issue with United & they were continuing to receive multiple complaints in this regard. They also said they would not be able to investigate any further unless I got that mystery number from United.
United kept giving me the runaround without giving me the number for over a month & then about 3 weeks ago they sent me an email saying they have unlinked this mystery number from my account & finally gave me the number. They also said I would have to get in touch with Marriott to get the accounts linked again.
I sent the mystery number to Marriott & asked them to link my accounts again with the correct Bonvoy account. They said that no account with the mystery number exists & my accounts have been linked correctly from their end for the past many years.
I sent that email to United & they responded asking me to wait while they investigated this further. 2 weeks later I get the generic 'Welcome to 2025 Premier Silver status' email from United. That was this morning. But the mileage plus department has not responded yet with what they are investigating.