I have an issue with materials stretching weirdly in Dimension.

Hello, I have a technical problem with importing a 3D object from Illustrator to Dimension. It is specifically related to the work with the materials as they stretch and turn into weird shapes when I want to apply them to my own 3D model (a basic bottle). What can I do? 
I will attach screenshots here for clarity. (The arch with the normal looking material is a default Dimension object and the bottle is my imported model from Illustrator) (I tried importing from Photoshop and have the same issue.)
Thank you in advance! 🙂