To receive the status update for SMS deliveries you need to make sure the SMS process is running . This can be confirmed from the Monitoring tab of the home screen in Adobe Campaign.
If you see the SMS process is running , you need to check for errors in the logs to find the reason why the Status receipts are not being received as SMS process is used to retrieve logs from the service provider and load them into Delivery logs.
Also , you may check the SR(status receipt) file in the server which will be present in the nl6/var/<instance>/mobile/<IP><login><port>/ in .DAT format. If the file stored here does not contain valid mobile numbers , it means Status receipts are not being received by campaign.