Walgreens

I have been buying Walgreens Nutritional Shakes for years specifically the one compared to Ensure. Then I found that after trying the one compared to Boost that not only was it the best tasting but it also has the lowest sugar and highest protein content. I buy quite a lot of merchandise at Walgreens and have for years since I live near the one I am referring to in my complaint. About two months ago I began finding that some of the 6 packs were "bad" and by that I mean they were tainted either by being heated too long or having some kind of rancid chemical put into it. I took one back and traded it for the one compared to Ensure which also has the highest sugar content. I thought at first it was the whole 6 pack but later found that the rancid ones were mixed in with good or normal tasting ones. I keep having to take them back and have sent one complaint and have kept in touch with the manager (possibly the assistant manager - his name is Patrick who is doing an incredible job and told me that an email was sent by the other manager but they hadn't heard anything back yet. The first time I drank one before I knew it was bad I drank quite a few gulps before I could taste it and when I did taste it I found it to be quite rancid and it gave me diarrhea. Since I have found out now that the rancid ones are mixed in with the ones I have to buy it first take out of the store open them all and smell it or taste a very small amount and then I mark it with tape. I just bought three last night and just discovered the four that I picked from two boxes to drink at work turned out to have three of them bad and by bad I mean some of the most awful tasting, send you to the bathroom drink I have ever tasted. Since I spend so much money on it I am also going to write o the BBB since I buy so much of it that when they run out at one store I stop at the one on 15th street on Capitol Hill. I wish you would please do something about this. The staff especially Patrick has been very helpful my returning the bad ones but I am tired of having to just about throw up after tasting enough of them. I'd appreciate it if you would please address this problem, find out why it is happening, send one to a lab so I know if I am being poisoned as from the taste I believe this to be a possibility.