Most people I know, have struggled in a relationship at some time, be it personal or business. The best way to solve it is still the Bible way. (Matthew 18:15-17)
First: go directly to the person. Try to meet in a neutral place, like a coffee shop. Be willing to take some responsibility, if the communication was not clear. We all hear things differently. Prepare to listen more than talk. It may take 8 full seconds to process an important question before answering.
Next step: involve one other person. Try to keep the matter as private as possible.
If that does not work, then go to the group or the next level.
Don’t expect this to always work no matter how hard you try. Some people like conflict. I once had a difficult neighbor. Their relative described the person as “mad at the world.” My best choice in that case was distance.