And they are also trying to take 1/2 of the money that I paid them instead of giving me the entite payment that I made.

If I did not ALREADY have the assets built up (had been saving for 20+years at that point) the answer would probably be different. 

If there is no cost savings don t use containers.Investigate use of ICFs for a build as you can build from foundation to rafters on a DIY basis in less than one week.

if it is just the financial side holding you back - let your bank be your partner… or see if you can borrow the money from a family member who knows and trusts you -  without actually partnering with them on the control of the deal itself (pay them interest - or even bring in on the lien to secure their position the first time) - but let them be the finances and you control the project. 

Are you not making money? 

If the owners purchased very recently or invested a bunch of money into the property it will be unlikely they will accept a lower down and an extended repayment period. - Little to no existing debt tied to property.

Many of my neighbors rent their entire houses and horse facilities out on a month to month basis, and they tell me they make a ton of money. 

You're asking them to agree to wait for their money for several years, assume the risk of you stopping the future payments, and they have to pay some taxes on top of it!

I lost money, hope you don't!

If so, you would need private/hard money so you can do renovations, and then AFTER you would do more of a permanent solution like a DSCR.