I know there is a din not to engage with goyim in litigation during the 9 days. I have a situation which has arisen and from a commercial point of view it would be ideal to issue a letter of demand this Monday (during the 9 days). It is not initiating litigation or court proceedings but just demanding payment for losses and damages. Because its not specifically court proceedings or litigation BUT rather an attempt at mediation would it be permitted?
Yes, the halacha is to avoid litigation, as it is a time of bad mazal so the outcome of the litigation may be adversely affected. Sending a letter does not have this risk and is not included in this halacha.