How to remove quotation marks in Table List

I have Import a .txt

Data = Import["files.txt", "Table"];

But the Data have the following format, I Cann't get the first column of Data eg. a,b,c, how to get rid of quotation marks in Data?

{{"a,10,20"}, {"b,10,20"}, {"c,10,20"},{"...and so on"}}

I have change the Import format like Data, Elements but all fails.

Any comments will be much appreciate!