So, your company decided that the antispam feature was of "no value"? Did you ask any of your customers? You didn't ask me. I found it valuable. Did you poll your customers? If you did, I did not get polled. Seems to me that the algorithm for detecting spam, once developed, is pretty static, not dynamic, and requires little maintenance. And you claim that the e-mail client program has its own adequate filters to take care of spam. Well, I use Outlook 365, and I haven't had anything land in my Junk folder for months, even though my spam settings are set to "Strict". I get those pathetic phishing attempts to update my bank accounts, and Outlook does not even block those.
Look, admit it, you guys blew it. Take a vote. Ask your customers. Or update your configuration settings to make the antispam feature an option, i.e., let the customer decide whether they want to enable the feature or not. This is a no-brainer. This is a terrible way to support your faithful customers. I myself have lost a lot of faith and on the brink of bailing out.