I was only able to resolve this bug yesterday (this bug happened to me a few months ago), I was still at level 17 and while I entered a server I was kicked during the loading and it happened this level reset bug and "locked classes" and yesterday in the hope of trying to solve this bug I went to look for more information on the internet (being that as soon as this bug occurred I also looked on the internet somewhere) and yesterday I found a topic on the actvision forum about this bug and the guy said he was able to solve this bug when he got to the level he was before he was reset (and with that guy had happened because of the prestige, different from me that was while I logged on to a server) and bought all the things he had bought before the reset and this inspired me to try the solution proposed by this guy of the topic, but I ended up without wanting to find the solution that I proposed while playing.
![black ops 1 computer cheats black ops 1 computer cheats](https://cdn.segmentnext.com/wp-content/uploads/2010/11/Unlockables.jpg)
For me, I was able to solve this bug when I reached level 10 (but that was not the level before my level was reset), because in this level I could modify the killstreaks (the killstreaks that i bought it was the blackbird), but then when I bought the killstreaks the game no longer presented "fetching stats" and could normally customize the classes.