lyane

Help Needed :
On March 16 I received a notification that my oath ceremony was scheduled and that I will receiving the notice with the location and time in the mail. It is been more than 2 weeks now and I have not received anything. From my experience with the post office in my area I am pretty sure that this mail is lost. The email notification I received says that if I don't receive it by April 15, 2015 I should contact them. However the next ceremony is April 14!! Since I waited a while to get scheduled I am pretty sure that I am scheduled for April 14. I know the uscis email always ask you to contact them in 30 days if you haven't received the mail, this notification is automatically generated and I am pretty sure that they don't check their dates to make sure that the day you should contact them is not after the day you should show up. What should I do?
- Can I just show up at the ceremony and hope that they will let me in if my name is on the list even if I don't have the letter?
- Is there anyway to know when I was scheduled for? I called customer service and they were not very useful
- Is it normal for the letter to take so long? I usually get the letter within one week of notification, all the time I didn't receive the immigration letter within 2 weeks, it was lost.
BTW, I live in washington DC and my oath is at the court in DC.
Please help, I have been waiting to get schedule for 3 months now and I dont want to take a chance to miss it..
Thanks