Poor service

Last week Friday my internet and landline went down, I reported the problem online ( which doesn't allow you to give a good description) as trying to call is impossible. and now my line has been cross connected so I report the problem and get a response two days later that the line is working which I agree that it is working but it is not going to me it is going somewhere else. Now my phone rings constantly for enquiries relevant to a different company who's calls I seem to be receiving and no internet. How do I speak to a compitant person about my issue? I need this resolved as I run my business from home.