What should I do if my landlord refused to send me a copy of my lease?
Where is your copy you received when you executed the lease? You did keep it didn't you? If not, you better ask your landlord nicely and hope they will cooperate because I know if no law in Colorado requiring a landlord to provide you with something already provided to you. Your location may be different, so search for landlord-tenant help in your area to see if there is another solution.