Changing of Pre-Booked Seat Requests?!

Have just returned from MCO on VS28 (24th Nov) flew on GVROY Pretty Woman, up until two days before this was scheduled to be the plane we flew out on, GVROS English Rose. I had pre-booked seats 63HK for the return flight, the night before we were due to fly checked the booking on the net to find out that our plane had been changed along with our seats! We were now booked in seats 53 H&K, separated by a total stranger in seat 53J!! Tried to change the seat allocation online, but was only showing two single seats at opposite ends of the plane! I called up Virgin in the US from the hotel, who could not give an explanation of why the seats had been changed. I asked if I could have my seats i'd pre-allocated and she said NO someone else has requested these!! I asked what else she could do to ensure the wife and I are sitting together? She suggested I phone the Virgin in the UK to see if they could do anything further. So thats what I did...made an International Call from the hotel phone to the UK, to be put on hold for 11 Minutes and for the call to be answered by the US Virgin Call Centre!!! (I and the US had not realised that it was midnight back in the UK!). Was very mad by this stage (even madder in the morning when I found out that call to the UK had cost me $65!) and the US agent told me to simply check-in at the airport and hope they could do something for us!
Next morning we went to the Downton Disney Check-In at 8.00am when they are meant to open, to be greeted with a queue of 35 people!, and we all stand there until 8.30am when they decided to open! I was hoping for an exit seat as I knew they would be available at check-in so we could sit together, but when I got to the front of the line - guess what .... all gone! Do you have any seats together I asked the lady?? No was the answer - 'its a very full flight you know!'. I then produced my Seats request confirmation and asked why these seats had been given to someone else? What makes them more special than us? I asked! She then taps away, makes a phone call and gives us seats 45F& G, not great but at least we are sitting together!
Sorry if I have rambled on somewhat!! I had to get it off my chest! It was a real happy ending (not) to our magical holiday!
Is this a common occurance - or was I real unlucky?? I realise that pre-booked seats are not guaranteed - but surely if you have had them allocated for 100+ days, you at least deserve to sit together!!??
Does anyone know why and how someone else can take seats like this?
Thanks for taking the time to read my rants!
Next morning we went to the Downton Disney Check-In at 8.00am when they are meant to open, to be greeted with a queue of 35 people!, and we all stand there until 8.30am when they decided to open! I was hoping for an exit seat as I knew they would be available at check-in so we could sit together, but when I got to the front of the line - guess what .... all gone! Do you have any seats together I asked the lady?? No was the answer - 'its a very full flight you know!'. I then produced my Seats request confirmation and asked why these seats had been given to someone else? What makes them more special than us? I asked! She then taps away, makes a phone call and gives us seats 45F& G, not great but at least we are sitting together!
Sorry if I have rambled on somewhat!! I had to get it off my chest! It was a real happy ending (not) to our magical holiday!
Is this a common occurance - or was I real unlucky?? I realise that pre-booked seats are not guaranteed - but surely if you have had them allocated for 100+ days, you at least deserve to sit together!!??
Does anyone know why and how someone else can take seats like this?
Thanks for taking the time to read my rants!