Assume I have never said this

[Xinfu]

Dear John,

I owe you a reply/an answer/an apology. If we see each other on campus/at university campus, and if we don't have lesson(s)/class(es), we shall talk something over. But if you're too busy or if you don't want to do so, assume that I've never said this/then we should rest the matter.

Yours sincerely,
Mary
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John is Mary's classmate; are my sentences above correct English?

[poli]

Because there is no context, it is difficult to answer this, but I will try.

I (feel) I owe you a response/an apology (if in some way Mary offended John) I we see each other on campus (in American English. Perhaps you can say at university in British English) we'll discuss this (or we will talk this over). If you're too busy or don't wish to do so, assume that I never intended to offend you, and I wish to put this matter to rest.

[Xinfu]

Thank you, Poli. But how about this?

John asked Mary a question, but in some way Mary at that time did not give a reply immediately; on second thought, Mary later thinks she should give a reply and wants to talk to John on campus. If John doesn't want to do so, assume that Mary has never said she has wanted to talk to John about that thing, and rest the matter (of wanting to talk to John). Would there be any change in your answer, Poli?