You hear all the time ‘build a relationship’, ‘build trust’ when talking about how to network and develop your business. Whether or not you are completely open and receptive, skeptical, or completely contrary, you won’t trust somebody for long who doesn’t keep their word. Trust and respect really do go hand in hand.
We should always give the benefit of the doubt at least initially, and give the person a chance to clarify or explain the situation — (an apology is very cool, but only goes so far after multiple times). No excuse for rude behavior like being chronically late or no-show for appointments, or failing to return your call or answer your email, even after you made 2-3 attempts. (…calling to say you will be late BEFORE you are actually late goes a long way.)
It must be qualified here that it is of paramount importance to be responsive (have a pulse), from the perspective of you having invited people to contact you anytime if they need anything or have a problem, and you would be glad to assist them. Don’t say it unless you really mean it. Make provisions for your customers to receive assistance if it is not your trip. People don’t like to feel that as soon as they give you their money the whole atmosphere changes and they can’t find you.
However fair is fair and ONLY IF the customer is following instructions and being respectful of your protocols, do you owe them the respect of a prompt response.(For example using the correct link or email address posted as the one for support.) If they feel entitled to be hostile there is always the blacklist filter.
If you tell somebody you will call them Monday – then call them Monday. Otherwise say you will call them soon (if you will). So rude to have someone waiting for a call that never comes. If you say you can deliver something by Tuesday, then you really should be on time. If you are not absolutely sure you can keep your commitment, then say ‘Tuesday or so’ (meaning maybe Wednesday or stretching it to the max Thursday). Be proactive if there is a problem – let them know before they get annoyed.
This type of genuine honesty extends to time limits, costs and quantities in advertising. If you say that the price is $1 cheaper until Wednesday, then the price should go up Wednesday, lest they see you are not a ‘man/woman of your word’ and it was just a ploy to rush them. The point is to mean what you say so people will respect you.
On the other hand, you can fudge a little and exactly on Wednesday announce you have decided to extend the offer another day, week or whatever. The point is to say what you mean so people will begin to trust you. Most sales/advertising people know that it is a legitimate ‘psyche’ to use scarcity (time limits, limited quantity) as a selling point that compels people to take action now instead of later or never. So there is a ‘thin-gray line’ here. 
