Q: Apple ID: change of the ID

Hi,

I changed my apple ID (from example@tt.dot to be example@gg.de), the reason was that I didn't want to mix my personal information and work related information (just got new phone from work). So I think I have now changed my new apple ID to all my devices (iphone 6 and macbook) and I started to create a new ID for my work phone. The problem is that I can't create the new ID because it is telling me that the e-mail is already in use. I try to create the ID with the a-mail example@tt.dot. So what can I do? I really need to use this e-mail because it's my work e-mail... So any ideas?