I am appalled reading this!! How can someone keep your data hostage like this? Especially (in this case) for no apparent mistake of yours! Really sad that a company like MailChimp who knows (or should know) what an Email list really means to a business would respond in such an irresponsible manner and deprive you of your own data.

I run an email marketing company called - SendX https://www.sendx.io and would be happy to help you in whatever way possible to get you up and running with Email Marketing again. Feel free to hit me up at mayank@sendx.io . Would personally ensure that our team helps you out with this asap.