Sewerage overflow side of house

I bought a semi-d house 2 years ago on northside Dublin. I share a driveway with the house to the right (number 12) as I look out my front door. My AJ (access joint I think this means?) at the side of my house has overflowed with sewerage 4 or 5 times in the past 2 years. Last June thinking the fault was with me I got a company out to clear the blockage. They identified a crack in the underground pipe at the back of no 12's house as the cause of the problem. The guy recommended fixing the crack with quick drying cement. However my neighbours didn't do this and the problem happened in March and again now. I was away when it occurred in March and my neighbours got another company in to clear the blockage. This company has said that the blockage is local to my house and not at no 12's.

So, I'm wondering how I go about resolving this...how do I know who's right? I will again have to pay for the drainage company to come out and clear the blockage. If anyone has any thoughts on this I'd be glad to hear them.

Thanks,
C.

Normally, it is best to talk to all of the neighbours on a row of houses. While problems will show up in one particular house, if it is not dealt with, it will affect all of the houses eventually.

Couple of years ago I had a similar problem - blocked drains four doors down, and all of the neighbours (bar one!) contributed to getting the drains unblocked as it was in all of our interest.

Minor point - Sounds like the 2nd company that was brought in by the neighbour found the symptom and not the cause.