It sounds like somehow, for some obscure reason, you got caught up in some actuarial table criteria which caused them to do this. It's unfortunate that they are unlikely to ever share why that is.
Most likely the reason the CSR can't say why the account got triggered is because he doesn't have the faintest idea. The computer raised a flag on the account and they'd have to find the programmer who wrote the code to find out why. And he's been assigned to another project, if he hasn't already left for another company. Been there. Behind the smiling faces, it's all chaos.