Were ranks ever reset?

5 bundle giveaways = level 1, it's correct

No but Mafia 2 is currently worth 0 because its purchase disabled, so thats messing with your level.

Previously, before CV was overhauled into a level-based system, it was purely on the dollar amount of games. When it came to bundled games, only the first $30 counted. Now, all bundle-game giveaways count, but are only worth 15% of their value. You can check here to see how much is needed in giveaways for each level