XBox One S from Costco Trial codes not working?

How long was the trial code for? Have you logged into your Microsoft account to check for an active subscription?

https://account.microsoft.com/account/xboxlive

many times those initial trial codes are 14 day trial (2 weeks). On-line gaming requires an xbox live gold account. You will need to either purchase a pre-paid code or sign up for a subscription if you want to continue online gaming.

I brought the Xbox one S at Costco after entering code for builders pack I see only the trail version not the complete version

Are you still having this problem? I just got an EA access code from costco and it's giving me the same error.. 1 min before I successfully redeemed an xbox $25 gift card from costco, but it doesn't like the Costco EA access one. I've tried it on both my
console and logging into web site with my account.

If the Download Voucher is nowhere to be fund in your packaging i would ask the customer service of the store you bought it from in your case Costco.

If the Xbox Game Pass Code or any other code may not work you should contact the Xbox live support via https://support.xbox.com/en-US/ so they can find out whats wrong with the code and help you get a new one or ensure the one you have will work.

If Costco tells you that the missing code is the fault of xbox you should also contact the Xbox Live support.

I hope that your problem will be fixed soon.