Targeted by rival seller with a load of 1 star reviews

Hi everyone so recently I seem to have become the target of a rival seller, on my main listing I sell around 15 items a day and usually get around 1-2 returns per week, however over the last week I have received over 25 returns, with some multiple orders and returns from the same people, i thought this was very strange and out of the norm, and then today I’ve realised that we have 5 new 1 star reviews all very similarly written, and all buyer profiles show that this is their only review on Amazon, I have also received 4 1 star seller ratings as well all again on the same day.

I also found an order from the owner of the brand that is our main competitor on Amazon, he has made the order to his name and address identical to the business address on their Amazon seller profile, I have also received a 1 star seller feedback an hour after the order from him before even sending the item out, which was then followed by a 1 star product rating again, I have tried speaking to Amazon and I just keep being told that there isn’t anything they can do and that I should click report a violation, but when I do that there is no option to do so, does anyone know if there is anything I can do about this as I don’t know where it’s all going to end, I have also had a big increase in returns and they are all immediately after the item is being delivered, I have worked so hard building up my listing and reputation over the last few years and have an average product rating of 4.0 which has now gone down to 3.7, I had just under 200 reviews prior to the 5 1 star reviews that have just appeared, hope someone is able to provide some insight into if there is anything I can do! Thanks in advance