Well, I never received notice and the Servicer presented that they had a "reference number for certified mail" and it was even printed on the letter! Who does this? Really? Hmm...(Don't get me into the letter generation department. It's a scam and they outsource it. Just because its ordered, doesn't mean it's actually printed, processed and delivered.) I do know for a fact that they assign these numbers and charge you for them on your statement under "fees" once it's ordered. This is 30 days in advance. So, if you make a payment then they might have to hold it to "make the letter true!" True story.
Fortunately CFPB laws have been further updated and the Servicer MUST apply payments even if payment does not incorporate fee. In other words, no suspending payments or non-applying payments to make it "appear" as if you are in 3 month default. (old rules were not to foreclose before 3 months, new servicing rules apply 6 month rule)
The NOI letter is a condition precedent. People win on this one in NJ. Krafy is right, screen shot or download what you find. If they don't have a signed receipt, then they don't have proof of delivery. Yes, they technically have to start over. And they will. In that sense, they are given the opportunity to cure defects in notice and proceed with a refiling.