Photobucket did the same thing I almost lost all of my photos that I had on it from my early teenage years because I almost missed the email(I was two days from the DDay)
Basically they decided that they no longer wanted their free tier and any photos that were stored on the platform as that tier had a certain amount of time before they would be deleted. The platform heavily tried to convince people who are on the free tier that the only way of getting their photos would be to pay for their premium tier for a month and then cancel but I was able to figure out a way to just download it it was hidden heavily in the settings behind multiple paywall triggers.
and what is that going to give them? The information that they have is yes, they have an account, and that’s also saying that they used an actual number and not a VOIP number for registration. but if they are asking via phone number, they will already have that information at hand. They won’t get any information about what chats that number is part of, or even any info really at all, anything about the account is encrypted and not visible.
If they are able to provide my phone number without knowing the info you said there, there is some other leak already involved, and either way they won’t get anything but a “yes he has an account and he was last connected on X”