I'd still write and complain. There's no way on God's Earth that he idiot should have been so insulting.
As the said: You're ver 18 and in control of your own affairs. If you decide to carry them out in a way that is at odds with how the Vodamuppet wanted you to act, that's entirely your business, not that of the Vodamuppet.
Insulting you like that is highly unprofessional and entirely unwarranted.
As I said, I'd be tempted to make a formal complaint; explain clearly and succinctly what went on, make clear how insulting and degrading you found their call and ask what restitution they consider would be appropriate.
I would also be very strongly tempetd to ask how they knew it was you that was browsing their website. had they recorded your contact details as part a login or signup with the website? If so I guess you'd have a cookie set and they were alerted by their systems when you loggin in again and looked.
If you use BT as your ISP,
have you ever had a Webwise alert page pop up when you logged in?
There's a trial being conducted by BT in league with an outfit called Phorm.
All your browsing is intercepted
Pages served to you are intercepted and altered.
From your intercepted browsing all non-personal (allegedly) data is reviewed for keywords which are then used to direct advertising.
Check out more
HERE