point system?

hi every time I invite someone I get a points for it, but when person that I invited register and then delete his account i’d like to get -1 point

for example: I invested my friend (i get +1 point), my friend invites someone (we get +1 point, I have in total 2 points my friend 1 point). the person that invited my friend after registration deleted his account so me and my friend get -1 point and now I have 1 point and my friend 0 points.

thank for a grate plugin secure invite, all working fine on WordPress 3.5.1

http://ww.wp.xz.cn/extend/plugins/wordpress-mu-secure-invites/