Still will not help. Although in theory it would work if a random third party paid off a person's ribbis (WITHOUT receiving any sort of compensation) if the third party in this case pays it off, since he is only paying off my interest because of my loan to him, which is ribbis as well. May still even be ribbis ketzutzah
Unless he is just preventing a loss for you. (Im just raising the possibility, it depends how you look at things.)
Besides, you can always make a simple Heter isska.
When approaching a rabbi, ask him how you can make it work, not if this is ossur. There are so many ways around...
This is how business is done
