Today I upgraded my account to Super Premium Hosting at Cpanel → Preferences → Account Upgrades, because my account was suffering from limited Inode problem (100% Inodes Used).
After the successful upgrade, however, I still cannot create additional files and the inode problem has not been solved.
Did you notice on which website you placed your order? InfinityFree is a free hosting service, and you just purchased an account on an advertisement partner: iFastNet.
Since you’re an iFastNet customer now, you may want to ask them how to proceed from here. Because buying an account on another company will not magically fix your InfinityFree account.