Transfer Account Holder role- Individual

Query: My ex colleague opened a individual apple developer account and we mutually published app there, but later on, he get separated, and move to an other town. I keep on using same account but he stopped. I don't have his contact detail as he have changed is contact and all details.

Now I want to transfer account holder role to my name, where as apple says one can only do it in below scenario.

""Account Holder transfers for individual members are granted when a minor reaches the age of majority and can receive the Account Holder role from their guardian, or when the Account Holder is deceased. Assistance is required from Apple Developer Support.""

Any Solution to my Problem?