All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.
Seeking assistance from people in matters that only Allaah The Almighty can do is one of the categories of associating partners in the Lordship of Allaah The Almighty. Allaah The Almighty Says (what means): {It is You we worship and You we ask for help.} [Quran 1:5]
The Prophet, sallallaahu ‘alayhi wa sallam, said: "When you seek assistance, seek assistance from Allaah." [Ahmad and At-Tirmithi]
Seeking assistance from people in things that they are able to do is permissible. The Prophet, sallallaahu ‘alayhi wa sallam, said: "We (Muslims) do not seek assistance from a polytheist." [Abu Daawood and Ibn Maajah] He also said: "Allaah assists the slave as long as the slave assists his brother." [Muslim and others]
Sufyaan Ath-Thawri said, “A man came to the Prophet, sallallaahu ‘alayhi wa sallam, and said, ‘What should I do if a man wants to usurp my money?’ The Prophet, sallallaahu ‘alayhi wa sallam, said: ‘Remind him of Allaah.’ He said, ‘What if he will not be reminded?’ The Prophet, sallallaahu ‘alayhi wa sallam, said: ‘Seek the assistance of the neighboring Muslims against him.’ The man said: ‘What if there are no Muslims around me?’ The Prophet, sallallaahu ‘alayhi wa sallam, said: ‘Seek the assistance of the Muslim ruler against him.’" [An-Nasaa’i] [Al-Albaani: Hasan Saheeh (Sound)]
Allaah Knows best.