In General, any case where you have someone at least some money makes sense to call the Debt! The only difference is that there are several types of debt and everything else is just their names.
1 Loan money from a friend, relative-a loan of a small amount of money for an indefinite period with the obligation to return "as I can".
2. Loan money from your Bank for a short period (a month, two) without interest using credit cards. Return within a month or two months is mandatory.
3. The loan of a large amount of money (mortgage, car loan, business) - is also a debt but paid gradually and for the use of this debt has to pay additional % to the Bank.

Well, in particular in Your case, I can only say that the word Credit - is that the loan without overdue payments to the Bank where you regularly pay and use the service provided to you.
And Debt-this in most cases overdue payment which you had to pay but could not in view of a number of circumstances whether it is debt for a utility fee , loan or mortgage.