When placing my design onto the item, I can’t enlarge it at all and it remains really small.
if you cant scale your designs larger on the printingarea the problem is probably the size of your image/the resolution. Your image should have 4000 pixel in width or height. If the system would allow to scale images that are way to small to the entire size of the printarea the result would be pixelated and the custumer surely would not buy it or return it.
Thatswhy your designs have to meet our requirements.
You will also find further information here:
In case that the resolution and size is not the problem you could send me your file via pm and I will check it.