When I flush the toilet the bowl fills up with water and goes down really slow and it doesn't flush everything down. Then it doesn't fill all the way back up with water? We live on the bottom floor of a apartment complex and also we have major sewer lines being replaced What do I do?

Your sewer line is partially stopped up. It could be anything in the line, even roots sometimes grow into old lines and it requires new lines to fix the problem. DrTom4444