When buying a package of lessons, lessons are credited to the student's balance in his personal account on the educational platform of Kodland, depending on the package purchased. With each lesson passed, the student's balance decreases by 1 and at the moment when the last paid lesson is completed, the balance account will be equal to 0. After that, you will be billed for the next payment via payment link to your mailbox. After topping up the account, the lesson balance will become positive, depending on which package was purchased after invoicing.