Why not do both? Open a few credit cards with low lines of credit, such as $500, and make those payments immediately.
If by buying a piece of property, you mean to build on that property, then by all means do so.
A combination of a few conservative credit cards and a small mortgage payment will build up your credit score nicely. Track your score and cancel the credit cards once the score gets high enough.
Otherwise, I agree with the other post. Go shopping for another lender. Also keep in mind that the ability to pay is based on both income and assets (which reflect the ability to repay the loan in case income goes down), so building your savings also will improve your ability to get a loan.