DLR report is gone from databse, please help!

[Bartosz Jozwiak]

Dear users,

I have been trying to set delivery status on  my kannel.
I see status of the message is stored in dlr table but as soon
as I turn on my phone and sms message is delivered, the entry from mysql 
database is being deleted.
Could somebody tell me how to store delivery reports which are not going to 
be deleted.
Or at least give me a hint!
Thank you in advance.
Bartosz