WHO GOVERNS BUILDERS -PURCHASED AN APARTMENT-CHIA (Bogotá)

Hello,
Anyone know who the governing agency over home builders is? We purchased an apartment which is not built for two years. We pay on time every month before we have to apply for the remainder at the end of the two years. BUT the builder applies the wrong amounts to our account on different dates all the time and we have our receipts, but now they are charging $300 US interest on a late payment that they are not applying correctly to the account and they are not correcting it no matter how much proof we send. Any suggestions? Thank you