DJI has the worst customer service of any commercial entity I have ever dealt with. And it's not just addressing issues such as yours, just getting answers to basic questions like upgrading the firmware is like pulling teeth. In part, I think the people who handle these matters haven't mastered English, but it goes beyond language skills.
I also had a loss of control incident resulting in my P3P falling into Biscayne Bay near my house in Miami Beach, where the current probably took it to the Atlantic ocean. Here is brief version of what happened. About half a mile from the Home Point in a huge and empty parking lot, I lost the signal. A few seconds later, the bird started an automatic return to home and I lost sight of it because of background clouds as it rose to the failsafe altitude of 400 feet. Eventually I received a warning on my device that the aircraft was descending. I expected to find it above my head, but instead it was about to land about 100 yards away in the middle of a busy intersection. I canceled RTH and took control manually, but the bird would not come towards me. I could make it fly in an arc, as if it were in Home Lock mode, but not toward the HP. It was as if there were an invisible barrier that it wouldn't cross. I struggled and tried everything, but it simply refused to approach until the battery ran out and it dropped in the water.
I requested a replacement from DJI (my bird was less than five months old) and provided the flight logs as well as data from Healthy Drones, which showed no user error whatsoever. DJI refused, insisting it was user error because I had continued to fly the drone until the battery ran out. Imagine that logic! Of course I continued to fly the drone until the battery ran out; I was trying to bring it home. DJI completely ignored the fact that, inexplicably, the bird just refused to approach the Home Point, and could not provide any evidence of pilot error. DJI also offered me a 15% discount on a new one. I refused; then it offered 20% as a final offer. In the meantime, I filed a protest with Paypal, which said it couldn't make a decision and we had to resolve it on our own. As I am a lawyer and was furious with DJI, I considered filing a class action lawsuit, since incidents such as these are common. But I decided it wasn't worth it and reluctantly took the offer. I looked at other options, such as Yuneec, but wasn't convinced they would be any better. Good luck in your dealings with DJI.