If you tell someone that you are going to do something for them then you should keep your word. Keeping your word is a must. Now sometimes things change and there is not a way you can keep your word. In that case you should always tell the person that you cannot do what you promised them,that is the right thing to do!
Not being man or woman enough to call someone and tell them that you cannot help them is not right. Having someone else answer your phone and claim they never heard of the person you are calling is bogus. Not answering a persons calls also is wrong.
When things are going well for you,you have lots of friends. When things are going poorly you find out who your real friends,and family,really are! If you do not treat people the right way do not get upset when it happens to you! Talk is cheap but you do not have to be !