If unpaid interest is added to a loan balance, later interest can be charged on that larger amount. The cost depends on the rate, when interest is added and how much you repay. Payments that exceed the interest can reduce the balance; debt does not inevitably grow forever.
This lesson follows one specified repayment plan so you can see where the money goes. If essentials or minimum payments are unaffordable, free debt guidance (opens in a new tab) can help with the actual situation. You do not need to finish the arithmetic before seeking help.