Question on leveling up
Help, I have scored perfect and the next levels are still locked. Am I missing something? Do I have to pay money to unlock the next levels?
If by level, you mean the row on the skill tree, then it will be locked until you complete all lessons on the previous row above it. This is the most likely situation - you still have lessons that are not complete.
There is an A/B test where you can't progress until a timer has finished, and you can pay to get past it with Gems. However, it should be obvious if you have that version or something similar.