Almost every day something happens to me in Brazil to remind me that I am rarely a valued client and nearly always just one more source of income for some money making enterprise.

It could be the phone company pestering me to take more services, nondescript bars charging $60 entrance fees, or the local supermarket, asking if I want a store card and offering next to nothing in return.

Last week it was American Express.

I never wanted an American Express card because I object to paying for a credit card in a nation where the  average interest rate is 238 % per annum. But I was forced to get one when I moved here because Brazilian airlines wouldn’t accept foreign Visa or Mastercards and I needed some local plastic in order to book flights.

Last week, AmEx tripled the cost of my card. Just a year earlier it had gladly reduced it, acknowledging I paid my bills in full and on time. I wasn’t informed of the hike and they gave me no explanation when I called their 0800 number.

When it bought American Express for  US$490 million in 2006, Bradesco boasted the brand enjoyed “considerable international prestige” and had in Brazil, “an excellent operational platform and a team of highly qualified professionals.”

It is hard to know if that was true and Bradesco’s clumsy management has soiled its reputation. (Although it is worth noting that Bradesco was third on the list of most complained about companies in Brazil in 2010, up from 29th in 2006.)

But whatever happened, there is a lesson here for Bradesco and American Express in particular and Brazilian companies in general.

Don’t punish your good clients and don’t treat them with disdain. The good loyal clients are the ones that will stay with you.