It sounds like you were offered a fast track renewal offer and the agent didn't register you properly.

However, it also sounds like you aren't particularly engaged with Hilton Honors. Hilton sent emails saying that in 2023 everything was back to normal regarding elite status qualification. And you clearly had so few stays/nights in 2023 that you only qualified for Silver status. Hilton also sent regular emails in early 2024 about "Diamond extensions" for those eligible.

So, although it sounds harsh, it appears that you would be escalating something (which would take weeks to resolve) only to drop down to Silver again in April 2025. (with only a 2-night stay in March you are way off the pace of 30 stays / 60 nights)

I recommend just becoming a free agent and/or investigating credit card options that might give you a head start to elite status.