What can be done if landlord said that the home will be sold to us but didn’t?

I would like to know what I can do on this matter. We rented a house for $3000.00 move in cost security deposit, $500.00 for each pet, $1200.00 1st month’s rent. The owner said after a year, he would sell this home to us, (I have 4 witnesses) and apply all rents and carry the loan. (He said this verbally). We were there for 4 years rented from (11/2008-05/31/2013). So after our lease was over, we asked if he would honor the verbal agreement. He said no he could not carry the loan so we continued renting. We did not sign a new lease. He did not request us to. In 2011, we were going to move, he sent an email to us a Letter of Recommendation. I have that. He said he did not want us to move, so we stayed. He sent us an email saying that if still interested, the house is $250.000. All rents will be applied so then we waited and he said that he could not sell at this time. We stayed again until 5/2013. He sent a certified letter saying he is selling the house for $375.000 and will be listing it. We have 1st right to purchase it. We told him that was too much so he said we could stay there until it sold as long as they could show it. We agreed. The real estate agent came took pictures of the home and listed it. We kept it in show condition. They had 1 prospected buyer that came to look at it. He wanted to show the home to this person. The agent called me on the phone and asked if he could show the home in 30 minutes and I said you have to give me a 24 hour notice. He said he was a good friend of another agent. I said no so they came the next day. The prospected buyer asked if we were going to stay until sold. I said yes then they all left. Then later that week after the 1st showing I receive a certified letter saying we have to move out 5/31/2013. When we left, we cleaned repaired a hole, replaced broken wall outlets, did a walk through with the owner he signed a statement that the house looked good. He would not give us A New Letter Of Recommendation to find a home.