Ebay Account Hacked

[follyfancier]

I could not log into Ebay this morning so I had to answer the security questions and get them to phone me with a pin number to log in and re-set the password,then after I logged in I discovered that another message was sent last night with new password details but I never got any email from them and it was not me who did it, the message sent by Ebay went to a different IP address and also several messages were sent to sellers supposedly from me about very expensive items for sale,I phoned Ebay straight away about all this but they do not seem to think there was a problem they just told me to change my security details which I had already done before I phoned them,I am puzzled how anyone could have re-set my password ,can they just ask for any phone number to be used without being checked first ? I noticed there was another choice where it said "Phone me and use this number" or give another number.