Just because I had couple of minutes free, I replied to their E-mail as follows:
Dear sirs,
strange E-mail received from you.
I can consider your proposal only after having received the following data:
• Registered business name
• Registered address, city, province, nation
• Intra-EU VAT no (if you are in Europe) or your Taxpayer's code
• Your history
• References
As you surely understand, a simple "GTA staff" and a gmail address are not an adequate "business card".
Thank you
Kind regards
As supposed, no reaction at all.
Claudio