Motor Stuck in the borewell


The depth of bore well is 520 ft. and 3- phase 10 HP motor is at 450 ft. It is 6.5-inch bore having 44 feet metal casing from the top. The motor is stuck there and unable to pull out. It hardly moves up by 1 – 1.5 feet only by pulling through chain pulley. Recently we did camera scanning of the bore in the casing first but at 210 feet there is a 6-inch ring (seems metal one) and there is 2 inch GI pipe and double cable of delta connected motor which camera could not let go beyond that point. Then we had inserted the camera in GI pipe which goes up to the check valve of a motor at 448 ft. The water inside the GI pipe starts at 390 ft. while in casing it starts from 40 feet. Since the motor got burnt down we need to pull it out and have deployed all the methods to take it out but all went into vain.
One of the contractors told me that it is not possible to pull out the motor but he can take out GI pipe and cable from the point of connection and after that new motor can be installed few feet above the old one. But installing a new motor would be a challenge as there is a ring at 210 feet. Even the possibility of bore got collapsed beyond 210 ft. seems distant and we don’t have visibility inside the casing beyond 210 ft.
What is the right method to break the GI pipe from the motor? Is it advisable to go for flushing before installing the new motor?. Pl. Suggest