I and my family are living in Canada. We all were having Canadian citizenship and US green card. During my last trip to US, I was told at US border to surrender my Green Card, as I am not living on permanent basis in US. How can I save my rest of the family members Green Cards, as I want to move them back to US for University after finishing school here in Canada. Also any legal way to get back my green Card.
Thanks

If your green card was taken back it probably expired, so when your family goes to the US theirs would be expired also (presumably if you all got them at the same time)

You will all have to re-apply for a US green card, how did you get them originally?

Through my family. My parents are there

Well then it should be a pretty simply application, you might also consider calling the US embassy in Canada and check what you need to get it back, maybe explain that you weren't aware when/ that it would expire.

Your permanent residence does not expire, the card (I-551) has an expiration. Unfortunately, it can be revoked by the CBP/CIS or abandoned/relinquished, by you.

Without more details as to the inspection or secondary inspection at the POE, it seems as if the CBP inspections officer determined you to have abandoned your LPR status by being outside of the US for too long a period.

Were you outside the US for more than 6 months continuously? Did you have a re-entry permit (filed on form I-131)? Did you file US taxes every year and otherwise maintain ties to the US?

The USCIS has the burden to prove you abandoned your permanent residence, please check with an experienced immigration attorney or certified specialist with details of your case.

For your family, you need to have them file for a re-entry permit. They must be physically in the US at the time they file for it. You should also be sure to get documentary evidence of the ties to the US.

You need to fight it because if the revocation stands, you can re-apply for permanent residence but, if it is a USC parent petitioning for you, and you are a married adult child, then you will be a third preference (FB-3) case, at this time for Canada about 8.5 to 9 years for the visa date to be current. Check the most recent DOS visa bulletin.

I would advise seeing an attorney immediately. I trust this was responsive to your inquiry. Good luck.