Any of the following could have happened:
1. Your system didn't send it or his didn't receive it. He may have read through all the e-mail he's received over the past few days, but he literally didn't get yours.
2. He may get so much spam that even though your e-mail was delivered, he didn't see it amist the other unopened messages. He didn't see it.
3. He may have seen that he had an e-mail from you, but he hasn't opened it yet to read it. He hasn't read it.
Yes, we "see" e-mail in English. We see the icon in our inbox it before we read it.
I'd try this:
Hi Peter. Have you had a chance to read my e-mail?
Then he could reply
1. No, I haven't gotten anything from you. (This could apply to 1 or 2 above, because if he didn't see it amidst the other messages, he may think he didn't get it.)
2. No, have you sent me one? My inbox is so full I have no idea who has sent me what.
3. No, sorry - I saw it in my inbox but my phone died and I forgot to [or I haven't had a chance to] go back and read it.
4. Yes, sorry - I haven't had a chance to reply.
5. Yes, of course, and I replied. Didn't you get my response?
Student or Learner