What is the ruling on saying: "Madad (help/support) O Messenger of Allah, reach me O Messenger of Allah, O Messenger of Allah supplicate for us," and believing that the Messenger is alive and visits them?

The statement "O Messenger of Allah, help me! O Messenger of Allah!" is a clear supplication to other than Allah, and it is disbelief that expels one from the fold of Islam. This is because supplication is an act of worship that can only be directed to Allah. The Messenger, peace and blessings be upon him, is alive with Allah in a life that differs from worldly life, and this does not mean that he visits people or attends their gatherings and supplicates for them.