Sat subject tests, paying for a new added test

I gave 3 sat subject tests on the december test day while I have registered only for two . And till now I haven't got any type of confirmation email from the college board that I have been registered for the 3. So how and when am I going to be charged for that extra test ? And if they are not the one to take indicative action in this then what should be next step go ensure that I get results from all the 3 tests . It's going to be 10 days after the test is am afraid that the 3rd test is simply going to be cancelled by the college board