Hi, After the winter, I found my air conditioner whole unit inclined towards the back at an angle which is quite big. The rear part is sinking down by more than 1 inch. I tried to lift it up the base concrete slab and put stones and bricks underneath to try to lift the rear base up, but won't help. I think the soil at the rear is too soft, or may be hallow. I am thinking to lift up the whole air conditioner unit, to make firm the foundation using small rocks and then sand, put back the concrete slab. But lifting up an air conditioner unit is a challenge. I don't want to break the air conditioner itself or its connected hoses. Any professional can give me some advice and suggestion, to help me to fix this problem, before I ask the air conditioner company to come to fix it? Attached two photos for your reference. Thank you.