why did my contacts disapear
Did you do a hard reset on your phone? (That would wipe out any personal files: contacts, pictures, etc on your phone). Provide more information otherwise people are stuck guessing, and will not bother making recommendations. Among other information you should include: What phone model you are using, if you have previously backed up your contacts, how long you've had your phone, what updates or applications you've installed lately, and if you've been troubleshooting some other issue, or experimenting with your phone settings. Have you cleared data on your contacts (that could have wiped them out as well). You're not providing any information for anyone to go off of, and until you do your problem will likely stay unsolved.
Are your contacts stored on Google, Verizon Cloud (Backup Assistant) or??? It can be one of any reasons. Which phone do you have? Check the contacts settings and make sure the account (Google, BUA, SIM, etc...) is the one actually displaying
If you use Verizon's Backup Assistant, that is your issue right there as it is always losing contacts, mixing them up etc... After you resolve this issue I would save all contacts as Google contacts and get rid of the nightmares you will have with BUA
I agree with Jakeman1 it always best if you can use Google instead of B.A.