Thats a common problem thats been happening to many people, join the official BO2 forum and post a thread in the support section, you'll see tons of threads of people getting reset after playing local. Unfortunately you can't do anything about it but you'll have to contact a moderator by posting a thread on the BO2 forums and they restore your account from a previous backup.
Post your problem here:
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And heres a thread of people having the same problem:
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