Can one rightfully refuse to accept Mishloach manos based on the idea of one should not accept presents, or a person who does so wrong since shalach manos was instituted to promote love? The other reason for shalach manos is that it provides food for the seudah, so maybe the idea of not accepting presents can apply (and he should not accept it)?
The issue is discussed in the נזר התורה journal of Adar 5767, and in responses thereof.
Among the sources cited by the author are the following:
I. Responsum in Yizchak Burstein's מטעמי יצחק. There, R' Burstein cites Chulin 44b:
R' Burstein explains that when the giver of the gift has some benefit (in the gemara, the sender would be honored if the esteemed Rabbi accepted the gift), the concept of שונא מתנות does not apply. Certainly, R' Burstein continues, by משלוח מנות where the sender is fulfilling a מצוה, the concept of שונא מתנות would not apply. (The discussion in the responsum is more detailed and complicated; what I've written here is just the essence of his argument.)
I would also add that the words of the Maharal (in נתיב העושר:א) are appropriate here: