Not even over best before date

I bought a few litres of milk as I do weekly shopping. We are not close to shops.<br> I usually buy crystal valley and never had a problem. So this week I opened my first bottle and it was all sour. Best before date showed 4th Feb 2016.<br> Opened next one also sour Best before date 4th Feb 2016<br> Opened next one same thing.<br> OK so now I have just sour milk for the week and not close to a Shop?????? what do I do??????