Motorola Solutions — issue in moto g5 plus

Address:

Dibrugarh, Assam, 786001

I am using moto g5 plus from last 6 months. I bought it from amazon in january. Recently while clicking photos by rear camera i have seen that there is a small black patch in every pics. Then i saw the previous pictures from before then also i saw that the photos have that patch but it was slightly small in size. Can you tell me what problem is this and what to do. There is no crack or anything in the camera lens.
Hope that you will resolve my problem and i will get a solution to this. Thank you