Is the plastic ring that's inside the basket that secures the basket to the housing screwed on tight enough? What does the o-ring look like? It's possible that it's gotten old and brittle/cracked and shrunken, therefore not functional anymore? (best practice to wipe every piece of rubber washer/o-ring with silicone grease before storing and again when taking out of storage). I doubt the basket or any other part of the pump has warped. Maybe cracked, especially if any children stood on it. I noticed that the basket sort of sags when it's full of water. Over time, I suppose that could cause a crack. I have propped mine up with a chunk of wood under the basket. We've had ours for 6 years, in full sun, every day, all summer and never had a single piece of plastic on it warp. You shouldn't need to get a hold of Intex. Check your model number, and then use it to order a new o-ring from them via their website or Amazon. Honestly, I wouldn't even do that. Considering how much in short supply all pool supplies are and how long it takes to get them delivered, I would empty the pump, and put some silicone adhesive or JB Weld around that joint, give it at least 2 days to dry and set, And deal with it, making sure to turn the valves off on both sides when the pump isn't in use it until I could replace it.
That would be strange since it doesn't go there. There is an large o-ring that goes around the outer lip of the lid itself so that when you put the lid on, it will be between the outer lip of the lid and inner lip of the basket. It should not be on the plastic ring that screws the lid down. .Please be sure to read the instructions for this filter pump. If you don't have them, Intex has them on their website available as PDF files.