offer accepted on duplex. On inspection, power off in one unit

[Eric Geurkink]

First time buyer, been looking and studying for about a year. Finally found one that the numbers made sense and made a good offer and it was accepted. I was told that the tenants were month to month and paying the rent when I made the offer. Now with this happening, I am concerned that they aren't. Inspection was rescheduled to Monday. I am thinking I want to end the tenants lease, but keep the other one if they are good.

What would you suggest, doing new background checks and making tenants reapply?  Getting documents of rent paid from the seller? Am I too late, already having made the offer contingent on finance and inspection, not tenant history, so I will just have to work through this?  Any pointers are appreciated!