Receiving notifications for getting achievements for games ive never played

I've been receiving notifications for achievements for games ive never played and its freaking me out

Hi,

did you own these games? Did you share the console with other people?

If not, I think that you should check your purchase history ( https://support.xbox.com/en-US/billing/xbox-subscriptions/check-xbox-live-bill )and
change the account password ( https://support.xbox.com/en-US/my-account/microsoft-account/change-microsoft-account-password) in
order to be sure that it has not been hacked.

If you not share your account with someone you got probably hacked. You should change your security details asap. Also you should check your purchase history.

Nothings been purchased and I've already changed the password but its still happening

Check all your details are correct at
https://account.microsoft.com change password again and check all email address etc. Then set up two step verification https://support.microsoft.com/en-us/help/12408/microsoft-account-how-to-use-two-step-verification

It should Have you been hacked? Might be worth changing password.