Text delivery report

I have a samsung galaxy 4 phone. I sent a text message and it came back as Delivery report Requested, Read report Requested
What exactly does this mean? Was the text received but not opened? Was it deleted on receipt without viewing it?. Was sender blocked? It's been like this for 3 days. Unlikely the person turned phone off. Or was that phone disconnected. This is the first time I received something like this.