Let's just say having communication skill deficiency in myself; i messed up initial part of the deal. But as i said he is the man of his words and i proceeded further clearing my head.
I have not(couldn't) yet provided him the invoice as i promised on sale thread but he understood the situation and we have mutually agreed upon a solution for which i have made a promise to him.
Thanks @Zino ! He is clear and pure hearted person.