What should i do with the stolen account?

Ok , so I paid $ 20 on Xbox Live card three months I met a guy anyway according sythe.org was a 29k gamerscore and a lv 42 aura I was surprised that this was selling cheap anyway I went for the first time in trade and everything went well ( oh well he was saying what his friends and realized he gave her ) after trade players look in the past and I realize that there are plenty of players just 14 hours yesterday and I face the guy saying how this account was used directly and asked if it was stolen and he said yes it was stolen anyway ........ im 14 years i have already changed the password information and everything before I knew it was stolen and the card type used three months already, but I just received an email password reset :-/ ( it aggravates ) MedlinePlus MedlinePlus anyway I do not know what to do : ( I can call Microsoft and report it stolen or I have to go because I paid for it MedlinePlus MedlinePlus I feel bad for the owner of the account because it is very hard to get 29,000 + gamerscore and played 170 games lol hes
MedlinePlus MedlinePlus MedlinePlus WHAT DO I DO MedlinePlus MedlinePlus MedlinePlus MedlinePlus Oh, and if the account was found stolen what would happen to me? I could only say that he had no knowledge of it being stolen