My husband was clearing the drains using drain rods. Unfortunately a part of the rod has got wedged inside one of the underground pipes. He now has to use the power hose every couple of days to clear away the waste. He is quite handy. Is this something he should attempt to clear.
You can try clearing the rod with mopre rods, from the other side but if that does not work please call a builder to dig up the blocked section and replace, it will not get any better, only worse, on its own.