Web Host Block Php Mail... Alternatives?

I send out almost 50 emails a day from a PHP program on my web site.

My web host wrote an email complaining to me.

Should I:

a) take their advice (and if so, do I need an SMTP server and how do I get one set up?)

b) change web hosts?

Here is the email from them:

Hi there,

Thank you for contacting us.

Please note that the script is being abused via a web browser to send out
mail. Please refrain to use the PHP mail() function as it is deprecated and
vulnerable to abuse.

We could possibly suggest that you take a look at using SwiftMailer which is well
documented and supported.

We have commented out all of the mail() function calls on your site.