Files with .xlsx or .xls extension. The data in the table can be divided into two cases, the first is two columns, and the second is three columns. When the table has only two columns, the first column is the phone number with country code, and the second column is the customer name. When the table has three columns, the first column is the country code, the second column is the phone number without the country code, and the third column is the customer name. The first row of table data is the header, and the second to last rows are the text.