On 2nd of December I had around 43.000 renown and when I logged on 3rd of December I was only left with 4900 renown. I was saving all that renown for new operators. Is there any way to get that renown back without going back to grinding ranked matches/terrorist hunt?
There does appear to be some suspicious activity on the account on the 3rd. I would suggest changing the email address/password on the account or adding the 2 step verification to prevent this happening again.