Sticker Manufacturer Help

Does anyone have experience moving their large inventory over to a sticker manu? I've been making my own stickers this whole time, but it's taking me too long to make them. So I figured I would start ordering my designs to hopefully eliminate that process completely.

I used Hub City Slaps because they came recommended. Orderd samples and they were great quality. Then ordered 5 designs. 4/5 designs were completely accurate to the proof. The 5th, the colors were off. I messaged them about it and was just told there was nothing they could do and that I should order samples of each design first to make sure. That would cost me 100s of dollars to do and time wasted to make sure they look right so I asked if they have a way for me to see all of my printed designs on a sheet or something to check colors. But they told me to order the 3inch sample pack of 10 stickers.

Honestly, idk what to do at this point. I know every printer is different, and that's why I wanted to just try to print a sheet so I'm not sinking money into stickers that don't look right. But it doesn't seem like many sticker manufacturers are willing to do custom orders. I guess my perspective is skewed because I worked in prepress, and we did stuff like that all the time to make sure people's prints were accurate.

I'm open to suggestions.