I have a case of Du Telecom 10 thousand Dirham. ...

You must pay this debt in order not to be prevented from leaving the UAE
According to Article (94) of the Executive Regulations, the following categories of foreigners are prohibited from leaving the UAE:
     Persons who are subject to a travel ban by the Public Prosecutor or any of his representatives due to ongoing investigations of criminal offences;
     Persons who are prevented from traveling by the competent court because of a case or claims pending before that court;
     Persons who fail to pay debts owed to the UAE government, and in this case, the Minister shall issue the travel ban himself.