What do you mean? You submitted it twice, once as a JPEG file and once as a PNG file? If that is the case, you shouldn't do that. You should only submit as PNG, if you want to submit with the highest "value".
If it got refused for technical issues (you should tell us always refusal reasons):
Your cutout work is not as perfect as it should be.
First, there are leftovers of the background. To check those, you can, in Photoshop, use the Stroke-effect. Leftovers appear as points, even if they are otherwise quasi invisible.
There are several of those in your picture.
A second point are round edges, where you should have probably sharper edges:
Those should also lead to a refusal if you submit as a JPEG. You can have sharp edges, when cutting out more than needed and reconstructing then the part which has been cut out too much. This trick allows for very sharp negative corners.
I hope this helps.
Thank you very much! I'm new, and your opinion is very useful for me.