IF and VLOOKUP by date overwrite problem
 

I’m using vlookup to fill in products in a sales tracker from my own data base in excel 2007. I am then using vlookup with date to record each daily sale as the sale is made to another sheet. On this other sheet I have it set up with By date, each day of the month as column titles. I can get my sales in to the correct dated column with vlookup with no problem. But when I clear sales from my sales tracker and start getting sales from a different account, on the other sheet where I currently have data (from the first accounts sales) it is over written with the new sales from the second accounts sales.

How can I separate the sales from one account to another with out over writing what is currently there? For example on the other sheet with days of the month for column titles, One accounts sales would take up 14 cells, G3 to G15. I’d like to get the second accounts sales to be listed from G15 to G28 and so on. There could be over 40 different accounts per day to list, so 40x14.

The code I’m using is:
=IF(B1=$G$1:$K$1,VLOOKUP(A2,$A$1:$C$15,1,FALSE),"- - -")
How can I get this not to overwrite data?