Who supported the levites?

The Levites were supported in terms of sustenance (i.e. food) by the other Israelite tribes as they had no land to farm. They ate the sacrificial offerings to God that weren't intended to be burned as in a second way, God supported the Levites as his offerings were gifts to support them. The Levites were priests, and carried out the ceremonies at the temples, and kept themselves sacred, and were thus able to eat the food worthy of God.