Susu Lembu Asli/ Goodday milk review: Spoil products when it still far from expired date and company worst action 1

I just bought a bottle of Goodday low fat milk Exp 30 11 q4 G446 13:29 03490 at 7/11 store at Permai suri and this milk taste like water even feel bitten and sour. I bought thi bottle on 22 Nov 2014

Right after i realize this bottle is spoil, i have come back that store and tell the sales assistant and ask her to taste it as well, her nam is Rosana. Therefore she replace a new one for me and let me open and taste it before bring back.However, i very upset in this situation because
1, i bought that mlik at midnight and have to go back that store also at midnight to complain.
2, i have write an email to this company and after 3 day, one guy call me and said they never experience this and have thousand bottle have been sole but non is as i mention. I have told him to check with the 7/11 and sale person, but then no reply. After 2 days another person name Theveena Chahil send me and email said cant call me, because i was in business trip. I have called her but then she said cant tell anything because she need to track for phone number. Then the next day, i have to repeat a same story then she said will meet me next Tues, then never call back.