Three options:

1) OP is just straight up lying

2) OP basically just blindly signed whatever was put in front of him

3) OP doesn't have much income but has a large net worth and payments were structured as monthly payments instead of a lump sum.

Edit: Please note I'm just listing possibilities. I'm not calling OP a liar, just that it is possible he is lying. Or that he is sitting on millions in investments.