Device stuck in repair department.

I must say that the level of this service is not what i expected. My device is stuck with repair department for a month now. When i call they always tell me that the IMEI number i used is the old one, but i did send a form with the correct IMEI number.

I provided my contact details: cell phone number and email address but i never receive any feedback. i need to call every after 2 days but getting the same story.

What else do i need to do now as this device is used for business purpose.