How long does it take for a username to be availiable after the account is deleted

I had a super old account that I hadent used in ages and wanted to transfer the username to my current, more active account. So I deleted my old account so that the username wouldnt be taken anymore. When I try to change my username on my current account, it says This username is not availiable. I was wondering if there is some sort of grace period or something until I can actually transfer this username. Is it a month? six months? Just wondering cause I really want to make this change before August.

I also would like to know if there is any way I can contact an instagram support member, preferrably through phone call, since they can probaby make this transfer a lot easier. This username is important to me becuase I remember using it for a lot of old accounts since I was a child, so I really dont want it to be gone forever or something.