What should I do, as I stole in the past due to poverty and am now unable to return the stolen money to its owners due to my financial inability?

Stolen money must be returned to its owners, for the Prophet, peace and blessings be upon him, said: "The hand is responsible for what it has taken until it returns it." If you cannot find what to repay with, or if they do not forgive you, then the debt remains your responsibility and must be repaid whenever you are able. It can be repaid in installments.