No feedback for three years now

i have an account which for some reson when i tried recovering a brand new account was creating using the same email address, this means i no longer have access to the first account because when i click forgot password it links to the new account, i have been writing and asking for assistance and at this stage I would like to deactivate the first account as the new one has gained momentum throughout the years. Instagram is a big comany and therefore needs to step up with thier support, cant have a customers battling to reach with account-related issue, who do you write to?