I have the same problem. I bought the gold bundle of Dragon Valley with Celtic Lands included. Dragon Valley downloaded well, and the launcher did say, "Celtic Lands is downloading." That was the end. Not one mention of Celtic Lands since. Not one trace of Celtic Lands is listed on the launcher, either above or below DV. But more importantly, Celtic Lands does not show up in the game. No registration numbes were given me with my purchase of Dragon Valley Gold Bundle.
In fact, most of the time, registration numbers aren't listed when worlds or EP's have been purchase as of late. We end up having to contact the EA's help team with our order form receipts in our cyber paws and our stories of missing registration numbers, worlds and what-have-you's.
I have been a fan of The Sims since the very beginning. I own every game, every world, and every EP there is. Out of all the Sims games that have been made, why is The Sims 3 so flipping complicated?! I really love TS3 so much and keep coming back to it. But there's so many glitches and missing things to The Sims 3. I too am really going nuts. In my honest opinion, EA seems to be concentrating so hard on The Sims 4, that our beloved Sims 3 is being left in the dust with more and more problems.