Some of you have made Pro or Master, gotten new Pro-tier or Master-tier clubs to celebrate, and then found that you could not use them in certain tournaments. This is because the game has a built-in rule that prevents you from playing in a tournament with higher level clubs if you signed up for that tournament while at a lower tier.
For example, if you signed up for a tournament as a Pro, but before the tournament ends you achieved Master and bought Master-level clubs, you will not be able to play that tournament with your new clubs. You should be able to play any new tournaments you sign up for with those new clubs. This rule helps to keep the playing field level as players get better and advance tiers.
Hope this helps!