Colorado law states that if a landlord does not return a security deposit or provide a written statement listing the exact reasons for retaining all or some of the deposit within 60 days, the landlord forfeits all rights to any of it. 

Here’s the caveat: the landlord complies with the law by mailing the statement or any payment to your last known address, regardless of whether you received it. 

If you believe you provided the landlord with the correct forwarding address and the landlord failed to follow the law, you may have a valid case against the landlord. 

If the landlord has willfully retained the security deposit, violating the law, they may be held liable for three times the amount of the wrongfully withheld deposit. The court can also order the landlord to pay the tenant’s reasonable attorney fees and court costs they paid to recover their deposit. 

Based on the limited details, it appears you might have a case. Legal procedures must be met to file a case against a landlord, such as notifying the landlord of your intentions to file legal action. Therefore, I recommend that you speak with a real estate attorney who has experience in Colorado landlord-tenant law. They can determine the validity of a possible claim and ensure that you adhere to the legal process.