I had a similar problem; mine only had 2 digits. I paid back around 3k in debt just spamming 2-digits, and bought a bunch of "try your luck" but they always have the same three events: free consultation, office refund, and unexpected refund. No new mechanics were revealed through buying any of them. I restarted the game, and after getting up to the try your luck (4.7k), I had only gotten 2 positive upgrades. I'm not sure if I'm just unlucky, but it makes it very slow to progress far.