Double standard with carry on luggage

I was flying to Sydney with other friends during school holiday. Everything is fine until the stuff told us we are unable to boarding cause we have too much carry on luggage, but actually, each of us are just have 1 lugguge + 1 hand bag and the total weight are below 7kg, other paper bag are the gifts we bought at Sydney and airport, even we told the staff our total carry on lugguage are not over 7kg, they still ask us stuff all the gifts into our luggage or we can THROW ALL THE GIFT INTO GARBAGE BIN...

So we told the girl who are working at boarding gate the lady who process the check-in procedure for us didn't ask us deal with our lugguage and we did double check with her to see is everything is ok, and the lady said nothing about our luggage; but the girl at boarding gate just said: I don't care, it looks you are carry too much lugguage on board, WHATEVER YOU WANNA THROW IT AWAY or you are not allow to boarding... Because we wanna go back to Brisbane ASAP, we were did what she said, put all the gift into our luggage. After we arrived Brisbane, our Macaroon are totally squeeze by the luggue and looks terrible. And the thing that are really mad for us is, lots of passenger are carry with at least 3-4 luggage, its not fair. Can someone tell me what happened to the service at Jet Star?