Simple, have them create a user id, and/or expose a "support id" somewhere in the system that lets you tell the support person which account record is yours.
I never want "communication" from an app developer unless I initiate it.
What about when you lose access to the account and don't remember what string of numbers you had to use after your preferred username because it's not a universal identifier that only you can use? In the case of the support ID, you'd need to be able to access the account to even view it.
I never want "communication" from an app developer unless I initiate it.