When you have set the combination of the digits, and you have forgotten the combination, there isn’t, unfortunately, a simple trick to fix this. If there were one, then others would be able to open your suitcase easily. Tricks spread quickly ... ;-). The only solution is to try all combinations (000, 001, 002, 003 to 999) of the digits. It seems like a time-consuming job, but, in fact, it doesn't take you more than 30 minutes.