This sounds more like poor customer service rather than an actionable civil matter. You should contact a Civil Rights Lawyer in your jurisdiction to discuss the specific facts of your matter. A local lawyer should be able to advise you regarding your rights, if any. There are no hard and fast rules regarding settlement amounts. Each case is dependent upon the particularized facts of the case itself. You can run a "Find a Lawyer" search here on Avvo to locate several lawyers in your area.
I do not think this is a case for the courts. If a litigant could sue and win for rudeness, many more would be millionaires. But rudeness is not a legal cause of action.
I agree with my colleagues that this may not be a matter for litigation. You may wish to simply address your concerns with the customer service department. That being said, there are not average settlement figures for age discrimination cases as they are all based on unique facts.