Problem in Letter of Recommendation

Dear All,

One of my MBA application, to a very reputed school for that matter, is caught in a weird circumstance. I need some expert guidance go get this problem sorted.

I somehow managed to get an LOR from Managing Director of one of our client company but as luck would have it the company has two MDs and they are both brothers using the same surname. I added one of them as my recommender and communicated about the same to them but I don't know where miscommunication occurred, the other brother testified and uploaded my LOR. It seems he can access other one's email. What's even more funny is that I got the confirmation mail from the school that they've received LOR from the brother whom I did not add as my recommender.

What should I do now? Should I write about this to B school describing my predicament or let it be as they've accepted the LOR? Everything is same. Company name, designation, family name, etc. Only the first name in the letter is different from what I wrote in my application. I'm getting really confused.

Someone please help.. Thank you.