Boyfriend curses me out when I don’t reply and stalks when I go online?

What do I do? My boyfriend texts me multiple times a day and I’m genuinely busy with uni work and stuff, so I don’t respond within the day sometimes. But he curses me out when I don’t, and even if I say I’m busy he says “clearly you’re not because I’ve seen you go online a few times today. You’re lying.”
Boyfriend curses me out when I don’t reply and stalks when I go online?
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