It was valentines eve and I reserved a table for t...

It was valentines eve and I reserved a table for two - 20 days in advance. I requested to be seated near the window with a view on the phone and even offered a reservation fees if applicable while confirming my booking and also called on the day in morning and i was assured by multiple people that its first come first serve basis.
I entered and observed that there were plenty of seats empty. I requested and mentioned that i was told its first come first serve. The girl at the entrance told that everyone wants that seat however its reserved for someone else. When i told that i reserved 20 days in advance.
Its was 9 PM and i was there till 11:30 however those seats were empty. It was illogical though but she didnt let anyone take those seats even for people who entered after me.
At first i was disappointed however my server was really nice and she cheered us up.