Hi and welcome to BDW!
I think what you're experiencing with Grand Palladium/Rocio is pretty common with destination weddings. That doesn't mean it's right, or that it's not frustration - it is SUPER frustrating. But it's common.
I'm not sure when your wedding is, and that could have something to do with the slow response. Many resorts won't focus on a wedding until 120 days out, or even 90 days. Not to say that you won't get responses, but you won't get super quick responses until it gets closer.
And then you will probably finalize all of the details once you get onsite. For instance, we had to change one of our entrees when we got to the resort - it was no problem at all! And yes, I freaked out over the slow response time and frustration of planning from a distance. In the end, it all worked out wonderfully!
Most of these resorts do many weddings, and so they focus on the upcoming weddings more than the ones that are farther out.
I see an active threads with other Grand Palladium brides - it may be helpful in answering some of your questions, or at least to see if others have experienced what you have.
There's also a couple of reviews (I believe this is the same resort!)
Good luck with all of your planning - I hope it gets better/easier from here.