im posting this in case anyone else ever looks for this answer.
there is no controls in linkpoint that allow you to disable the customer receipts that are sent from linkpoint to the email address of the purchaser.
I called linkpoint - they can do it on request from thier end. However you have to have the merchant account security info (so get that from your client before you call).
but instead of doing the above - i just decided to change the email that is sent to be sent to my client. So now my client (website owner) will just receive the confirmation email that comes from linkpoint.
took this:
$LinkPointAPI_optional[0][$nextIndex] = "billing->email";
$LinkPointAPI_optional[1][$nextIndex] = "".((isset($_POST["email"]))?$_POST["email"]:"") ."";
and changed it to this:
$LinkPointAPI_optional[0][$nextIndex] = "billing->email";
$LinkPointAPI_optional[1][$nextIndex] = "orders@mydomainname.com";