I'm sorry to hear that you're dealing with this particular situation.
Unfortunately, there's not a way to disable the "missed call" notification on the phone that I was able to find. You might see if it's possible with your carrier to stop sending the "missed call" signal for calls coming from a specific number, but you'd have to ask your carrier. Unfortunately, the phone doesn't have an internal block for missed call alerts, unless I believe, you turn them all off.
Does that help?
Hi, i have a number on auto reject, but ideally if that person (whose a right nuisance ) call me, I dont want to see a Missed Call message for them either - can i set the phone so that I don't get a missed call message for that number, but still get the missed call message for everyone else?