XBOX 360 GAME

My mom took my son to buy a game for his xbox on Saturday. when she got home there was a age restriction on the game 18 (grand theft auto). when she took this back on Sunday to the CNA at kollonade the refused to took the game back. I understand that the game was opened BUT firstly WHY did you sell the game to my son if you can see that he is not 18. Then you have the RUDE and CHEEEK to ask why did he walk around with so much Money - what does it have to do with you or the whole of CNA!!!! And then the MANAGER OF THE BRANCH has the cheek to say if she was there she would have not sold the game! DEAR MADAM IF YOU WHERE THERE??? WHERE THE HELL WHERE YOU THEN IF YOU WHEREN'T THERE????? This is really not ACCEPTABLE THAT YOU CAN SELL A GAME TO AN UNDERAGE CHILD - SO YOU WILL SELL HIM SIGARETES AS WELL AND ANY ****OGRAPHIC BOOKS THT HAS A AGE RESTRICTION ON IT!!!! I need someone from CNA to investigate this and tell me what you are going to do about this as I really don't want the game!!!!! AND THEN I WOULD LIKE THAT PERSON TO BE TOLD THAT SUCH BEHAVIOUR TO ANY CLIENT WRT THE AMOUNT OF MONEY BEING KEPT IN A HANDBAG HAS NOTHING TO DO WITH YOU OR ANYBODY