Urbano

What support did you contact? For contributors, ther is only one support relevant, and that is contributor support: https://helpx.adobe.com/stock/contributor/help/Need-Help-Contact-Us.html

And yes, watermarks on submitted pictures are a no go. For this forum, you can add them, but you should state that you did submit without. And the watermark should not cover the image, so that an image critique gets difficult. A Watermark on submitted pictures would result in a Non-Compliant refusal. But please note: the moderator refuses on the first error he or she sees. So, there may be multiple different errors in an image. 

If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html