Coke is flat!!!!!

I am sick and tired of buying 2ltr Cokes and them either flat..or going flat after the first glass. I cannot tell you how many bottles I have had to throw away..and yes I refrigerate and seal them properly!!. I buy cheaper drinks for the kids like spar brand and they stay full of gas till finished yet Coke can't manage that?? Why the heck not?? I don't know anyone that has money to throw away..but coke doesn't seem to find that and issue. I'm sick and tired of this!!!! I am aware that they have a problem with one of thier plants. .but here is an idea. .FIX IT AND DON'T SEND OUT INFERIOR PRODUCT!! I don't know...just a thought!!!