Typically in the past. i usually asked for my support ID to be merged. but for whatever reason when i get support id (ex: 123456) merged with support id (ABCDEF). typically a few hours or more later, maybe instantly, it tends to change to (GHIJKL, note these are just examples.). What am i usually doing wrong. cause i believe it’s supposed to keep the new support id you have with your old, but it tends to change it to an even newer one for me.
But when i ask for milla to merge 2 usernames, that typically never happens. what gives 
Right now i do not seek to get it merged (cause i completely forgot my old one), but this is a question i want to know why it happens.