I have also done some cases. I just think it's a shame if the artist delete the images are for you. Without notification. The pictures are really for me, I paid. And if you can not track it back, it is difficult for the credit. Sounds as if I were a thief. *.*
You should always declare this in the description. In any case, just say you didn't do it, but it is work you have paid for, or else you could get into trouble :-/.
As a rule, they know me. I never write down - that I have painted. I have paid for it. They know my characters. And anger - you can talk to me. People know I can not draw - they also know I would not take me this insolence out. Why would someone say something? Or who would make trouble? That would interest me even once.
There are so many artists who make no label. Since you can think what you want. *.*