Custom PHP site - secure email configuration

There are two current issues I like to resolve.

Issue 1.
Configure email settings using secure authentication, currently configured with PHP mailer which is using default port 25. this has been disabled by vendor.

Response from vendor:
What I would advise you is to make sure that the messages you are sending out from the application are fully authenticated, using SMTP authentication, and not using a PHP mailer script.

Additionally, the messages should be CAN SPAM compliant.

I went through the spam incident in question and while the email itself is legit, there have been an abnormal amount of such emails that originated from your site in a short period of time. This is why it is much more likely that your website's registration form is being abused. As far as I can see the form is completely insecure and can be submitted by a bot quite easily. There were multiple submissions from the same IP address in the spam of 30-60 minutes.

Issue 2.
Configure existing forms with ReCaptcha.

Response from Vendor:
you will also have to secure that registration form with a strong form of visual verification - such as ReCAPTCHA

I also have some further changes to my online portal so please provide me your fixed price to resolve the above issue plus per hour so that I can keep that in mind.

Many Thanks
Vikas