You did receive a letter from advaro …
because there is a bill you have not yet paid. The creditor passed it to advaro, to collect the debt from you. Since you have not paid on time, additional costs have occurred which you have to pay.
To avoid further costs it is important that you pay the amount stated in the letter which you received from advaro within the set time limit.
In some cases it is possible to extend the time limit. If you think that this is necessary in your case, you must contact advaro immediately. You can apply here.