If the waste drain serves only your house then you are responsible for its clearance up to its interception with the drain which serves other houses. If it is a shared service (for example with three or four other houses) then it is the responsibility of either your water/sewerage company or the local authority. Where the responsibility lies depends upon when your house was built. Pre 1936 (I think) and it is the water company�s responsibility, after that it is the Local Authority. (No, don�t ask me why this is. I did so once and wish I hadn�t).
I would suggest that if it is your responsibility, having gone to 25 feet with rods already, I would engage a professional drain clearance contractor. Their fees, whilst quite high, are not enormous and it will save you a lot of time and bother.