I've barely used the account the past year, I think they try to disable inactive accounts to seize the assets.
The account was used more intensively before that and has been properly verified for at least 2 years.
The fact that they use personalised links is quite disturbing, I definitely won't be using Bittrex any longer.
I hope your funds weren't in there (in fact never ever leave your valuable assets in any exchange in case you are going to be off trading for a long time)
These crypto exchanges are like unstable weather, you never know what kind of requirements or regulations they can come up with tomorrow.
The personalised links could have been tailored for the territory you come from since different territories have slightly different regulations.