Why couldn't they just refinance instead of robbing banks?

It's revealed over the course of the film that Toby and Tanner are robbing banks to pay off a $40,000 mortgage on a farm that forecloses at the end of the week. Then later revealed that oil was discovered on the land. In the end, the farm is producing $50,000 worth of oil a month.

So if you're a farmer in Texas with $40K in debt, but are sitting on top of an multi acre plot of land that that has an oil reserve worth millions, is there still no possibility of avoiding foreclosure? Another bank can't refinance that loan? An oil company or investor is not available? And that you're only recourse to save your property from foreclosure is a bank robbing spree?

What am I missing?