eBay wont let me change my username even though name follows all the rules..advice please..

[harmony0426]

Hi there, trying to change my username but keep getting this same message from eBay; 

'Your username can only include letters, numbers, full stops, asterisks, underscores or hyphens. Please review our policy.'

My new name has 7 letters so not sure what the problem is. If name is already taken surely they would say?

Any ideas or answers welcome.

thanks