ok, these are the applicable rules of civil procedure: "Writ of garnishment with notice of exemption and pending levy" means the exclusive procedure through which the personal property of any kind (other than earnings of a natural person) in the possession or control of a garnishee including the credits, debts, chooses in action, or money owed to the judgment debtor, whether they are due at the time of the service of the writ or are to become due thereafter, is required to be held for payment of a judgment debt (a "Writ with Notice"). A Writ with Notice shall be in the form and content of Colo. R. Civil. P. Form 29.
After entry of a judgment when a writ of execution may issue, a Writ with Notice shall be issued by the clerk of the court upon request. Under such writ any indebtedness, intangible personal property, or tangible personal property capable of manual delivery, other than earnings of a natural person, owed to, or owned by, the judgment debtor, and in the possession or control of the garnishee at the time of service of such writ upon the garnishee, shall be subject to the process of garnishment. Issuance of a writ of execution shall not be required before the issuance of a Writ with Notice. Service of a Writ with Notice shall be made in accordance with Colo. R. Civil. P. 4.
Following service of the Writ with Notice on the garnishee, a copy of the Writ with Notice, together with a blank copy of Colo. R. Civil. P. Form 30 shall be served upon each judgment debtor whose property is subject to garnishment by such writ as soon thereafter as practicable. Such service shall be in accordance with Colo. Rev. Statute. Ann. 1354.5107(2)* 1 Service of a Writ with Notice upon the garnishee shall give the court jurisdiction
over the garnishee and any personal property of any description, owned by, or owed to the judgment debtor in the possession or control of the garnishee. Colo. R. Civil. P. 103.
The issue is whether you received notice as soon as practicable. Your best argument is that this did not occur as you were not notified until nearly 30 days later.