Naturalisation certificate returned in unacceptable state - info for replacement

Received my supporting documents today in a very bad state, completely bent and handled with no care at all. Following the advice in this thread I've called and tried to get through the complaints department without luck. Bear in mind that the lady that first picked up the phone suggested that this was a problem for the shipping company to deal with, I said I didn't really agree with that.

I'll let you know how this progresses.