Manhole cover

The manhole cover in Simon's drive keeps overflowing with sewage flowing into his garage and garden and he says that Southern Water won't do anything to fix it.
He has contacted Southern Water with no joy and Cappagh Browne, Southern Water's drainage team, have been out once but never came back to finish the job.
As a result he has had to deal with the situation himself using his own pressure washer multiple times.
He's been dealing with it for a while and is being really affected by it, his partner’s grandchildren can't come round, damages in his garage.