How to remove "Total Sum of" text on the columns

Hello, Deo,
 
Thank you for reaching out to us. 
 
Flexmonster provides an option to hide aggregation labels like Total Sum of, Sum of, etc. in the column/row titles. 
This can be done by setting the showAggregationLabels parameter to false, for example: 

options: { 
   showAggregationLabels: false 
} 

Here is a JSFiddle example for illustration: https://jsfiddle.net/flexmonster/ecet3kw6/ 
 
Please let us know if this works. 
 
Best regards, 
Vera