Hello @InaMay, We can understand why the quick notification panel dropping would be bothersome. Here are some steps we recommend.
1. Test the phone in safe mode. It's possible there is an app triggering the drop-down. https://www.samsung.com/us/support/answer/ANS00062983/
2. If the Quick Panel continues to drop while in Safe Mode, we recommend backing up your data and performing a factory reset. This would resolve any software concerns you may be experiencing. https://www.samsung.com/us/support/answer/ANS00062029/
3. If the Quick Panel still continues with the dropping, the phone will need to be evaluated by a certified technician.
You can use the following link to find a list of service centers in the U.S. that can do the repair: http://www.samsung.com/us/support/service/location or by contacting customer support at 1-800-726-7864.
For assistance outside the U.S., please use this link: https://www.samsung.com/us/common/visitlocationsite.html