BANNER experience HELP!

I just got 2 banners from Costco. I have used them two times (indoors) and this "sag" from left to right, diagonally seems to be getting worse. They said that the humidity can cause sagging. My horror is that if it looks this bad now what will happen in mid summer when I am doing festivals. It really is visible.The supervisor said that she got a vinyl banner and it was the worst thing she ever done. I feel like I was taken to the outer limits.....I know that I see everyone using vinyl banners with their tents. Does anyone have this happen? The Costco guy measured one and it was clearly off in the center, he thinks it was due to the sewing and he will have to first see who will pay for it....I told him that I already paid $115 for each of them, I wouldn't pay more. Do you guys have this problem? should I use a different product?

Hey Saloner,

if you post once, in one subject matter, we can all see it. Posting three times doesn't help, but does make it harder for people who answer to piggyback off ideas that others have suggested.

When I come here, I have to click which section I want to read. so sorry. I really need to know what to do, I have to order 3 more banners and have to know what I should order.
Sorry if I made it irritating to you

Not irritating, just trying to maximize your experience.

Try this, it'll change your life:
http://www.facepaintforum.com/search?search_id=newposts

That link lives right above all the subject posts on the main screen, right below the "subscribe button."
The link says: "View posts since last visit "

That way, you'll see everything new that has been posted without having to go to each section. Magic!