Parmalat Everfresh Milk Bad

I purchased a full box of 6 cartons of the Everfresh milk and today I opened one to warm it and it appeared thick and after warming it it was smelly and had thick clots of milk and looked off. My frustration is that this isn't the 1st time I am having this experience and now I am stuck with all this cartons that are supposed to expire on 12/12/2020 but already are expired