(keitai-l) Crediting/rewarding i-mode users

I'm aware that with i-mode, users can purchase services etc. by getting
this charged directly to their phone bill. Is there any mechanism in
place to do the opposite, i.e. to reward someone, by directly crediting
their phone bill with a certain amount? 

(If it's of any relevance, I'm talking about i-mode in Japan rather than
Europe.)

Any comments appreciated, thanks,
Mario.