Ow, that must have been quite aggravating...
Mixing Flats with Rounds will probably lead to a set of uneven tone and tension, I wouldn't recommend it. ( But I believe it won't be harmful to your Bass as a short term solution)
I've heard that some companies replace such defects free of charge, you could try contacting the maker or the store about the breakage.
Last edited by Alex Da Silva : 07-12-2013 at 02:53 AM.
Reason: A more complete answer to the question