We have a couple of bags arriving on a cargo flight from Egypt tonight (used household goods, no value declared) We didn't pay for door-to-door and need to pick the suitcases up ourselves. Does anyone know where we need to go, and the hours of the office? No luck searching online for information and not getting any answer at the customs office.

Have you asked the shipping company?

Good Luck with that! They will most probable be at the customs office, where they will ask you do declare every little single thing. After that they will most probable ask you to depart with a couple of thousands of baht to get your things.