Customs asking for electrical safety certificates for coffee roasters.

I imported a small batch of electric coffee roasters from a supplier in China through Alibaba . Just a few units to test the local market. The supplier said they had CE certification, so I assumed everything was fine.

The shipment arrived at the port last week but customs is holding it and asking for electrical safety certificates. The supplier sent me a generic CE document but the customs officer says it is not sufficient. They want specific test reports for this exact model.

Has anyone here imported small kitchen appliances or coffee roasters before? What documents do customs usually require ?