how doe one stop telephone sales calls usually in the evening ,and mainly indian gentlemen ?
Contact your phone company (e.g. Eircom) and ask them to register your preference not to be called. Check with utilities and make sure they've registered your preference. Never give your real phone number to hotels when checking in, or in surveys, registrations unless there's a real need for it.
Any marketeer who calls you after 30 days of your preference being registered will need a very good excuse.
That said, if they're operating from outside of the state, there's not a lot can be done about prosecuting them.
If the call is from an Irish company, ask for the full legal name of the company and its legal registered office address. Log the time of the call and any names give and report it to the DPC. That said, I received numerous calls from a company calling itself 'Talk-Talk' and they always hung up before giving this information. They are legally required to answer the questions.
Usually the callers are using predictive dialling computers. These dial you, then listen for your 'hello' and then transfer the call to whichever 'Indian' gentleman is free to sell you stuff. In the USA there are gadgets that can fool the auto-diallers into thinking your number is engaged or they've reached an answering machine, in which case they go and look for another victim.
An alternative strategy, more fun if you have the time is to lead the marketeers on and then floor them with inane questions. I've known some friends to ask the staff about their working conditions & if they're unionised.