At fault accident 1yr ago, other person still fighting

April of last year I was in an at fault accident where I rear ended a rusted out early 2000s Chevy Suburban who came to a sudden stop after taking off from a stop sign. This accident occured at speeds of ~10mph and it left minor damage to my vehicle and none to the vehicle I rear ended. I have had many discussions with the person handling the case from Progressive (my insurance) who has agreed these people have ill intent. 6 months after the accident happen, nothing had been paid out to them and they had been refusing to cooperate with my insurance. Eventually, $600 was paid out for minor property damage, later it went up to ~$3k for "bodily injury", and now its nearly $9k for other "bodily injury". My insurance company, last I spoke to them, stated the bodily injury claims are extremely questionable due to the low speed of the impact, no visible damage to their vehicle excluding preexisting rust damage, no doctor visits, no hospital visits, etc and all of sudden the entire family had supposedly seen a physical therapist, which my insurance company questioned since there would likely need to be referral. This family lives down the road from me, and all of sudden have new vehicles (still have the old rust bucket they were driving before), and seemingly in great health as I see them out walking and playing. My insurance went up nearly $60 last renewal, now with the increased payout likely will increase again in my next renewal. What can I do to fight this? Do I have any options? These people are EXPLOITING this situation for everything they can. I heavily suspect they are committing insurance fraud in one way or another at this point.