Fractional Captain reported conducting a go around due to an aircraft stopped on runway.

Narrative

Called and reported a 5 mile final clear to land with aircraft proceeding us cleared for low approach. Less than a mile at 200 feet. That was cleared to lower approach; landed; and did not leave the runway environment. Cannot talk on tower as they were having conversations and paying attention to the aircraft on the runway. Finally got in touch with tower and we're in the midst of go around when they called to go around. We executed go around and could not get the tower to issue go around instructions. There were numerous aircraft in the pattern. We finally got heading and altitude and switch to approach for safe instructions. Tower was too busy to notice that the aircraft they cleared for a lower approach; had stopped on the runway after trying to get in touch with them we were finally able to keep the go around. I don't know what the aircraft on the runway was going to do. Suggestions: Getting safe; go around instructions from Tower after repeatedly asking. Tower and aircraft stopped on the runway at the time need proper training and instruction on safe operations. They need to be less distracted on aircraft 20 miles out and on the aircraft in the pattern and on the runway.