I deleted a sub-account by mistake and want to create it again. When I try to recrete it, it says the user name is not available. After a sub-account is deleted, how long does it take for the user name to become availanle again so that I can use it again?
Deleted usernames/aliases are typically unavailable for ~180 days (six months).
If you contact tech support you might be able to have it restored. I would recommend asking *very* nicely. It's technically against policy (since you have to select the account, click delete, and OK the pop-up confirmation to delete a sub), but sometimes they make exceptions.
Verizon has options for contacting support on their Contact Us page.