My hotmail account is locked

Hello,

I have a Hotmail account of last 15 years and has been locked out without any reason . I have tried in last 2 weeks several times to go on site and follow the process of retrieval but get a standard email that due to security reasons my account can't be opened and I have been advised to open a new account . This is really very frustrating and hugely disappointing as I have a number of contacts and useful information in the account . Being such a large company of repute , I am sure they can offer other means to authenticate the account . Is there a number I can talk to ?

Sincere thanks for the help ,