Most of my Muslim neighbors do not pray, except for few. I tried several times to encourage them to pray by giving them audio material about the importance of prayer and the punishment for abandoning it. I even spoke with some of them about that issue. However, all my efforts were in vain. Could you please tell me what I should do?

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 ‘alayhi wa sallam, is His slave and messenger.

Dear questioner, you should keep on reminding and advising your neighbors, since, guiding a single person through you is better for you than possessing the whole world or having great wealth as was stated by the Prophet, sallallaahu ‘alayhi wa sallam [Al-Bukhari and Muslim]

Allaah Says (what means): {And who is better in speech than one who invites to Allah and does righteousness and says, "Indeed, I am of the Muslims."}[Quran 41:33]

Moreover, try to use different methods in Da‘wah, such as offering your neighbors audio material delivered by different speakers that address issues like, the status of prayer, the ruling of the one who abandons it, and the description of Paradise and Hell.  You could also use Islamic pamphlets and magazines. 

If you do your best trying to guide them, then do not be bothered if they refuse to adhere to the truth because guidance is something that only Allaah The Almighty controls; Allaah Says (what means): 

Allaah Knows best.