I'm a big believer in going to the person/business to let them know what problems you are having and give them an opportunity to fix it...
It is disappointing when you do this and you do not feel that you are being heard or your problem is being resolved... But, as mentioned, there are other avenues to pursue this - avenues that may be more fruitful to you in the long run..
As I understand it, the policy is about direct criticism of vendors. This (to me) does not mean that people cannot ask for recommendations of vendors from other members who have had positive experiences (Yes? No?)
Cheers,
Mark