Say it with me again everybody, tumblr will not use tumblr to contact you if there's a problem with your account. They will email you. Posts like THIS:
Staff's blogs are @staff, @support, @engineering, and @changes. NOT a random string of numbers with a profile picture and banner mocking up the main staff blog.
If you get tagged in a comment or post like this, DO NOT click the link provided, DO NOT follow the instructions, and DO NOT give them any of your personal information or banking details, which apparently they are asking for, going by a few of the comments on the version of the post I got tagged in.
Report the blog for spam and then block it. There have been A LOT of tumblr based scams going around lately, like the zombie bot takeovers, so please remember to always safeguard your info online, find support numbers and links independently, and don't click any suspicious links!