code: private void cancelTimers(
  			List<org.mobicents.slee.example.sjr.data.RegistrationBinding> removedContacts) {
  		for (RegistrationBinding binding : removedContacts) {
  			ActivityContextInterfaceExt aci = (ActivityContextInterfaceExt) this.activityContextNamingFacility
  					.lookup(getACIName(binding.getContactAddress(),
  							binding.getSipAddress()));
  			// IF exists end the activity, SLEE will cancel timers, remove aci
  			// names, etc.
  			if (aci != null) {
  				((NullActivity) aci.getActivity()).endActivity();
  			}
  		}
  	}
docs: Simple method to cancel pending timers for contacts that have been
  removed
  
  @param removedContacts