You should be refunding the money consdiering your advert clearly stated quaife diff and it doesn't have one!
WORKING ORDER? THE HOUSING HAS HOLES, THE GEAR TEETH ARE WORN, 5 GEAR HAS PLAY AND THE DIFF IS A STANDARD 6 BOLT, DIDN'T REMEMBER YOU MENTION THAT ALSO THE FINAL DIRVE WAS 4.2 S1 EITHER DID YOU? CLEARLY YOU WOULD OF KNOWN THAT AS THE RATIOS WOULD HAVE BEEN SHORT AND TOPPED OUT AROUND 135MPH, PLUS THE FRONT MOUNT LOCATION IS BROKEN.
THEN YOU STATE THAT 300 QUID IS A STANDARD GOOD BOX MONEY? YOURS IS COMPLETY FUCKED SO COUNT THAT AS 50 QUID TO SAVE FACE!
NOW STOP WRITING SHIT AND START DOING THE RIGHT THING!