Bad mattress - don’t buy this brand

New to Canada and don’t know there is a warranty for the mattress. The mattress actually lost support in the first year. My son is under 180 lbs with 179 cm tall. His sleeping time is less than 6 hours per day. He keeps complaining the back pain. And his friends remind him that mattress should have warranty. We tried to get the warranty but in vain. Normal sweating is treated as stain and void the warranty. It’s ridiculous. The mattress is totally unqualified. Don’t buy.