Refurbished geyser fitted as replacement

I recently had a claim with Aquality plumbing works (Fogi) when they removed the old geyser i told them to leave it behind they advised that its a requirement for them to take it out.

When the new geyser was installed and the electrician visited my place he pointed out a dent on the geyser and advised that the black marks on the element looks like it had previously been used and I've been given a refurbished one.

This is extremely concerning as I was not expecting this as I was told it would be a new geyser.

I would like to request an assessor come and evaluate the geyser and whether or not it has been refurbished. In addition could you please confirm if its a requirement for the old geyser to be removed from the premises if not I would like the geyser returned, the staff responsible for the job were extremely unprofessional and rude, as an elderly gentleman I expected a lot more patience and courtesy when speaking to them instead I was met with arrogance and hostility.