Thanks for contacting Syncfusion support.
Query 1: How to add a label at the top of each column?
You can achieve your requirement by using the Adornments in series.
Please refer to the following link for further information.
Query 2: Need to refresh the data.
You can achieve your requirement by implementing the INotifyPropertyChanged instead of removing the series and enable the ListenPropertyChange property in series.
Please refer to the UG link for further information.
We have prepared the sample based on your requirement. Please find the sample from the following location.