Stay away from Arjuneshwar Mahadev Ashram and Kameshwaranand Ashram, and from cheats like Pandit Ramanand Tiwari and Anurag Guruji. In fact, most of these ashrams are packed with fraudsters!
To have any ritual performed, contact any Maharashtrian (Marathi) purohit from the official Purohit Sangh website, because they are authorized, trusted and verified, and only they have the legal birthright to conduct kaal sarp dosh nivaran puja and other shanti poojas in Trimbakeshwar.
Good luck, all the best, and OM NAMAH SHIVAYA!