Estoppel by silence and Failure to Police a Mark Domain Names - Defence

[marly]

I have a domain name registered for 6 years, and now I have been contacted saying i'm infringeing a mark.

Estoppel by silence—Estoppel that prevents a person from asserting something when he had the right and opportunity to do so earlier, and such silence put another person at a disadvantage.

Where a plaintiff fails to act or chooses to remain silent with regard to the continued unlawful use of his trade mark or copyright in a Protected Work and this creates an impression in an infringer's mind that the plaintiff consented to the continued use of such intellectual property, this may constitute the necessary representation to establish a defence of estoppel.

There is evidence of use over a substantial period of time in order to be able to rely on the defence of acquiescence in an infringement action.

Do I have a defence? how does this work with domain names.

[lordbyroniv]

You may have a laches argument. I don't know what "estoppel by silence" is.