Have you recently inquired about interest rates on any internet site? If you put your information in at any of those types of sites you likely consented to being contacted. When they call do you ask them where they obtained your phone number or other information?

You can use the link below. http://www.dora.state.co.us/real-estate/complaints/Complaints.htm

Loan officers are regulated through the Department of Real Estate (DORA) in Colorado. If they work for a bank they may not be required to obtain licensing, so you would need to contact the bank directly

Many people are unaware that if the do an internet search for rates or use one of the on-line credit report services, like FreeCreditReport.com, part of the boiler plate that you must accept for the service grants them the right to market your information, which supercedes your registry on the National DNC list. Odds are if you are receiving calls from multiple lenders you have done something to trigger the contacts. Assuming this is the case and you really don't want the calls, inform each one at the time they call to "place this number on your DNC list. Do not call this number again. this number has been registered with the National DNC and any further attempts to contact me will result in a complaint to the Federal Trade Commission". This will at least get that firm to stop calling. Good luck.