How do you deal with vendors who ignore grooms?

I know you guys have written before about wedding vendors who totally ignore grooms, but I'm looking for some super practical, step-by-step guidance on how to make it clear to my vendors that if they keep ignoring my fiance, they stand to lose our business.

Does anyone have any copy-n-paste conflict resolution-style phrases that I can use to make it respectfully but completely clear to vendors that there are TWO OF US planning this wedding?

We love one Tribesmaid's simple solution (“p.s. please include both of us in your reply”), but we'd love to hear from those of you who've wrestled with this. How did you make it clear to your vendors that they needed to include your partner?