This has happened twice in six months now. We order our tickets months in advance and we never get to sit together.
They randomly seat you and then tell you if you want to sit together you need to pay an upgrade fee. This is not the way to do business. My wife is scared of flying and wants to sit next to me, but not with Delta she has to sit next to a complete stranger. When you call they pretty much tell you there is nothing they can do for you, but you may upgrade for anywhere between $42 and $75.
I am already paying between $400-$500 per ticket and now i have to pay more to sit next to my wife. This is a terrible way to do business.