Change the main and billing account

I am writing to seek your assistance with transferring the main (billing) account access. Our colleague, who was responsible for managing this account, has recently left the company. As a result, we are unable to manage user accounts or pay the upcoming bill.

I am currently one of the users on this account, and you may verify that I have been the only active user for the past two months. To ensure continued access and uninterrupted service, I need to transfer the main account access to myself.

Could you please guide me through the process of changing the main account access to my email address?