My toilet and tub both baking up we have tried plunging and the wax ring gave out so we replaced that got the 50 foot snake and snaked the roof vent put every thing back together (ran the hose water in the hole first)everything seemed fine and it all started overflowing as soon as we went to use it we went ou and opened the clean-out and it had a lot of back pressure_we are on city sewage and water and the kitchen does not seem to be affected what is next?

When you had the house cleanout open when you flushed did it back up. Explain more about this "back pressure".

the kitchen does not seem to be affected If your home is a older home that once had a septic system the sink doesn't tie into the house main.
It sounds like the problem may be between the house and the city main but I don't have enough information to make that call. Give me all the details you have, Back to you, Tom