how can i understand to witch account is paired my apple watch

Hello! I send my watch to the repair center in Greece, but they told me that i have to unpair it

from my account or device. I have unpaired my watch from all my 3 devices, but they told me

that apple watch is still paired to a device! I do not have more than 3 devices!!!

So, how can i understand to witch account it is paired?

Thanks!