When you exceed the conditions of your first purchased license model, e.g. by reaching over 500,000 streams on Spotify etc. than you have to contact us (email@example.com) for upgrading to a higher license, to be legally safe with copyright. You the only have to pay the rest amount of the higher license model.
For example you previously bought a Silver license for 29,99€, to upgrade then to Platin you have to pay the rest-amount of 170,-€ (199,99€ – 29,99€ = 170€).