Questions: Family & Friends

So, my friend stopped replying 3 weeks ago. I sent a 2nd text 6 days later... still left on read. And then, I sent a 3rd text 7 days after the 2nd. It was basically a farewell message. Told them that they should have been more honest, etc. My friend's been posting on their social medias ever since they stopped replying (showing off the fact that they were living their best life).

My "friend" replied to me 8 days after my 3rd text. They said that "I didn't do anything wrong, and that they went through some dramatic events lately, which they'll tell me about later... and that they hope that I'm doing good, and that they think about me even though it doesn't really seem like it".

It's been one day. Haven't replied yet. I don't know what to say, but all I know is that I will not block them. I mean, what if what they said was true? It's probably some made up excuses, but what if?

So is it okay to just leave them on read for a couple of days? Y'know, I'm not 100% ready to reply (haven't found the perfect response yet) and at the same time, if they do still think about me, then maybe leaving them on read will make them understand how I felt when they did the same thing to me.