Paulo, Experience is needed, of course, but if you are told the right way to tackle a problem that you have not come across before(by people who have carried out this type of work many times), and decide to ignore them then what was the point in asking in the first place?
Yes you got paid for the job, but I doubt you will get any more work from the customer. Its not a case of earning your wage for the day, its building relationships with companies by carrying out the job to the best standard, to make sure they come back.