Gamertag Original Owner with Suffix

The numbering suffix is used to differentiate gamertags. A change to the gamertag system last year enabled users to have similar gamertags to other, existing players, but to distinguish them from the original one, a numeric suffix is used. If you wish
to change your gamertag, there is a charge of US$9.95 (or local equivalent) to do so.

No. The suffix doesn't automatically drop off if the original tag frees up because it's already part of the gamertag.

With the updated gamertag policy, you can still use it even though someone else has it, but you will be given a suffix to differentiate you from the original owner. Otherwise, as long as the tag is in use on the system, you cannot use the tag. The tag system is in use on other Microsoft services, so even if it is not in use on an Xbox, it may be in use elsewhere.

You can use it, but you'll be given a suffix to differentiate you from the original owner. Otherwise, the original owner would have to change it to something else or if they don't sign into their Xbox account for 5 years, the tag will be freed up for use. There's no way to know exactly how inactive an account is as they may be using it elsewhere on Microsoft's services.

I apologize but there is no number that we can call.

But in regards to your case, the reason why there is a suffix is due to the Gamertag already taken and if you own the original Gamertag, the workaround of using it on your new Microsoft account without suffix is if you will change it into something else first.