Student or Learner
Sentence: "Sorry, I couldn't reply to you in/on time."
My question: What preposition would be correct to use in the sentence, in or on? Would it be wrong say the above sentence like this "I couldn't reply to you sooner/promptly"?
Regards and thanks.
I couldn't reply to you in time = I couldn't reply at any time before the specific deadline you gave me (or before something else happened).
I couldn't reply to you sooner = a general apology explaining that you would have liked to have replied earlier but you couldn't.