He left me on read then said I miss you?

Why would a guy say and do this? How should I respond? I don't want to offend him or cause and argument?

Context 3 nights ago I tried to return his missed and he was busy
he messaged me 5 minutes later saying "just busy working atm x"

Me: "I really appreciate you letting me know, I hope to ehar about your day later tonight x"

I politely let him know I appreciate him getting back to me and informing me he is busy at the moment. as appose to ignoring my call/ leaving me on seen.

3 days later:

Him: "are you free to call?

Me: I'm at work, I can't call at the moment can i give you a call when I finish work? x "

Him "when do you finish work x"

Me " I finish at 9:30pm, if it's urgent call me and I can step out x"

Him "not urgnet, just wanted to hear how you are going x"
"I hope you have a good shift x"

6:45pm: Me "thank you (cute nickname) x"
"I look forward to talking to you after work x"

He left my message on read
9:30pm: I finished work at I didn't call or text him after work as I got the impression he didn't want to talk to me or he was busy.

2am: Him "I missed you tonight x"

10:30am: he sent a picture that I haven't opened.

Should I let him know, I didn't message or call as I thought he didn't want to speak to me as he left my message on read and didn't acknowledge it? Should I just brush it off?
Why say I miss you after he's the one who left me on read?

He left me on read then said I miss you?
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