Super pixilated!

I was really disappointed in my shirt. It looked really pixilated and off. It could be the file I'm uploading (jpeg) but I'm not no expert so I don't know how to convert it over to a scale-able file. Regardless, it looked nothing like the proof. I feel like once the product has been made and if it looks horrible OR if they're aware the file/print might not be the cleanest/smoothest, they should notify the buyer. I'm not sure how they're printing the shirts but it seems like there was an under layer of color and when the top layers got printed on, it didn't align so there's a "line" under the print too. It looks horrible close up. I've been testing the complexities of Sticker Mule's prints and if you're looking for basic prints I haven't really had any problems. Multi-colored and more complex prints though are a different story. They have not been turning out good.