Dear Mr. Erickson,
We have known each other for many years because of the business dealings that we have done in the past. Because of it, I feel that we have already developed a kind of friendship and trust that is hard to find in the business world. But an incident happened which has caused what bond we might have formed to be tarnished.
In this connection, I want to convey to you my sincere apologies for any misunderstandings that happened between us. Our companies have been dealing with each other for some time and I do not want the good relationship that was established between us to be broken by so trivial an incident.
Our phones will always be open for your call. I will be more than happy if you can accept my apology and continue the good relationship that we had through the years.