Unnecessary & Aggressive

Been with 123-reg some years. I have domains and associated email accounts with them. I received a most aggressive email this morning telling me that I must IMMEDIATELY change my password as it was insecure and that if I didn't comply my account would be closed in 14 days time. I duly contacted 123-reg, only to be told it was a genuine email and that my password was insecure and needs to meet the requirements set out in the email. And that it is to my "benefit" that I comply or have my account closed!
Funny thing is a couple of months ago, I was forced to change my password when I went to login, I was "blocked" from logging in until I set a password that "complied". This new password met all those requirements. Yet they are now telling me it is insecure and a security risk!
I have other email accounts with them that are not used very often, yet those accounts haven't had such emails demanding password changes on pain of account closure! In fact I would have understood if that email had said those other accounts needed a password change.... they weren't even mentioned though!
So far I have not had a straight answer out of 123-reg about why they are being unnecessarily aggressive about this one email account. I have simply been led around the houses and been repeatedly told to change my "insecure" password or my account will be closed!
Why said long-standing customers aggressive and threatening emails? Why not answer a simple question?