Yes you do have a blockage that's the only thing that causes a 'Backup'. Open the manhole the toilet feeds in to.
1. If you can see the channel at bottom of m/h the blockage is between bowl and manhole.
2. If manhole is part/full then go to the next manhole check that if that is clear it's between manholes which is a rod job but duck tape the rod joints to stop joints coming apart always turn the rods clockwise to keep them tight together, never anticlockwise. If maholes are clear try rodding back from the first manhole towards toilet if that fails try.... Boil a bucket full of water pour in a good strong measure of caustic soda.....wear rubber gloves caustic burns skin.....pour the mix down the toilet bowl, wait about 5 minutes or until flows out then mix another lot do the same when it clears try flushing if it still backs up you may have something like these toilet cleaners that fix to rim stuck in the pipework and are buggers to remove can't advise how you may have to get specialist to tackle it. check house building insurance it may be covered. Hope this is clear enough.
Bob, October 2009
