what should i do if there is an apple id on the watch but i dont know it and the previous owner doesnt know it either

Hi

Activation Lock prevents unauthorised use of Apple Watch if it is lost or stolen.

The previous owner should have removed the lock before selling their device.

To be able to pair the Apple Watch to your own iPhone, you would need the previous owner (who may not be the seller) to either enter their Apple ID and password on your iPhone or to turn the feature off via https://www.icloud.com/ (by signing in with their Apple ID > Find My iPhone > All Devices, then select the Apple Watch > Erase Apple Watch > Next until erased > click X next to the watch).

If you cannot arrange for the previous owner to do this, then you should, if possible, return the Apple Watch for a refund.

You will not otherwise be able to use the Apple Watch. There is no way around this security feature.

Apple will not advise you of the previous owner's contact details, nor will Apple pass your details on to them.

More information:

About Activation Lock on your Apple Watch - Apple Support

There is nothing you can do. If the former owner will not unlock the watch it is useless to you.

You can reset the phone.

It's useless. If you can't return it and get your money back, turn it over to the police.