Mitsubishi xpander rusting
 

so guys i need some advice, i bought a brand new mitsubishi xpander in October 2020, and thw car came with 3 years of warranty from mitsubishi, after about a year, i started noticing that certain parts of the frame started rusting, i immediately called the dealer and fix and appointment to have it repaired, then less than a month later, it repaired in the same location, hence i decided to inspect the car myself, and found more rusting spots and found new ones starting to develop, went to the dealer and they fixed it, but 2 weeks later they all reappeared, the rust seems to be spreading rapidly too, i contacted the dealer and said that i don't want this car anymore because it is clearly defective, but they are refusing to either refund me or provide me with a similar vehicle. What should I do? I sent it for repairs twice already but the problem comes back again and is spreading. I have these than 2 years of warranty left on it. Please note that the car is well maintained it is not left out in the rain or anything. Only has 9400km on it. I have attached a few photos, but there are many more spots
https://cimg3.ibsrv.net/gimg/mitsubi...c34982b9ae.jpg
https://cimg1.ibsrv.net/gimg/mitsubi...bbe429f7b9.jpg
https://cimg4.ibsrv.net/gimg/mitsubi...3434b4db96.jpg
https://cimg9.ibsrv.net/gimg/mitsubi...2616fb96d1.jpg