We have my step children we are in the state of Washington. The custody was done in California. The mother still resides there and she gave us guardianship of them. We have had them for the last 2 years and she has had no contact but by phone. After 2 years she has decided that she wants to come and get them. Do we have to let her take them?

She still have legal custody of them if there was never a change in custody at the court. That was what was needed.

The fact you have had the court grant your guardianship for the last two years, you need to file for an emergancy order of custody.

Also even if the children are living with the non custodial parent, that parent legally has to pay child support if they did not go back to get that changed also.