Been through this and posted about it on another thread.
Let me share the details here so that others can benefit from our experience:
1) FEMA maps are OLD... you can view them yourself
HERE. The newest ones are on line are from 1988. Since you didn't mention (or I didn't catch it) where you were buying, you can look this up and see for yourself.
2) You can dispute the bank's findings. Ask if there is a formal process for this and disclose that you have found no other units in the complex have flood insurance. (In our case, it was that an insurance underwriter in Idaho was misreading a FEMA map. No joke.) It's likely there's a time limit for this sort of thing. Going to another bank may not solve the problem. This seems to be common lately. In our case, we had another survey and the findings were share with all parties. We pushed hard for everyone to communicate and ON TIME - no delays. (I'm a good ankle nipper when I have to be.) We resolved it at that point - it went no further for us but still cost $400 more than we'd planned.
3) Be willing to get a new survey of your property. This may cost money.
4) Be willing to get a lawyer. We all know this WILL cost money. (I know a couple of good ones that are experienced w/ this sorta thing. PM me if you want names.) (We didn't have go that far - thank God. One of our two neighbors did and they won.)
5) Go to the town planner and talk with them about your case. They may be your best resource for not just maps but maybe even other similar cases.
6) Can you ask your future neighbors for help? We ended up giving a copy of our certificate from the last survey we had done to two of our neighbors when they had the SAME problem. BOTH got out of having to pay flood insurance. It might be worth the try - maybe someone in that complex has already dealt with this problem.
Keep cool. Document everything (and I mean EVERYTHING.)
This isn't impossible to get past - I don't envy you having to go thru it.
In our case, we found out about the "need" for flood insurance and responded with "what do we have to do to make this go away!" We were closing in 3 weeks and expecting our first baby in 9 weeks. (Little did we know that baby would come in 3 weeks - just a couple of days after closing.)
Good luck!