Hi there Yooyooo,
Sounds like you had very similar problems to us with regards to dealing with reception and checking in your guests. I also had many issues like that but left it out of my already lengthy review. Like me, glad to hear that your wedding was everything you had hoped it would be! Thanks for sharing your pics - beautiful!
It seems like there was definitely some huge issues with your shuttle but I wanted to add some info as well, hopefully to put you a bit at ease as to why this company had your contact info.
We also booked through Barceló.com for ourselves and our guests, and one week before hand we went online and paid for everything. The only amount we couldn't pay for ahead of time for any of the reservations was the shuttle amount of 73 USD return pp, which we paid at the resort when we arrived. I thought this was weird since we were able to pay thousands of dollars ahead of time, but couldn't prepay the shuttle, so I asked the gal at the front desk about it. She said it's because they don't always know which shuttle you will be transported on. Over the 3 weeks that we were there, we saw our guests come and go on a few different company shuttles even though they were all booked through Barcelo.com so clearly there are different companies that share the business/workload, etc from Barceló.
With regards to the Vacciones Barceló shuttle service specifically, we also arranged for the shuttle as part of the option during our online booking. Shortly afterwards I received the corresponding emails from Vacciones Barcelo, with references made to the correct/corresponding reservation number as we received with each reservation that we made. (Their layout was exactly as you copied and pasted to your post here - asking for flight info, etc.) We provided all the flight details and we received shuttle confirmation back from the company ... some came immediately, others took a few weeks. The confirmation page had clear instruction on what we needed to do once we got to the airport, photos of the guys in their yellow shirts, and clear direction not to go with any other shuttle company or else we would not be reimbursed. They do this because there are lots of shuttle companies at the airport not working with resorts directly that do try to scam you! When we got to the airport the guy was waiting for us with a sign with our names on it, we got on the shuttle and carried on to the hotel. As I said there was certainly something sneaky happening with your experience, but it sounds like almost infighting amongst the companies that do service Barceló, or a bad employee trying to scam you ... but this is why they had your name, email etc.
Hope this helps a bit!