Any one help me with this one????

Ive ignored my ex N now for 4 days as im trying to do NC he knows the times and days to see our little boy, so no need to contact me however he has been txting all wkend....iv managed to not get sucked in.... But this morning i get this tx which says...'I dont know weather its being arrested or you that has made me feel like a bad dad but i feel horrible this morning and you not texting me back has just made it worse, are you enjoying punishing me? ' He got arrested for punching a taxi driver last week, and couldnt see our son becoz he was 2 ill from what had happend, how ever i later found out he was with his new girlfriend.... Do i just not respond still and stick to NC he knows the days and times he will be seeing our boy already so dont need to speak to him do i? Any one help me??? Xxxx