Square tubing connectors

Long story, but I ordered my kids one of the "in-ground" trampolines. Son wanted one for his birthday back in June, but everywhere we looked locally an online were out of stock. Wife signed up for notifications when they were back in stock at a few places, and about 8-10 days ago she got an email from one of them. Shipping took a few days, and when it got here yesterday morning via FedEx, it was obvious the box had been damaged in shipping. It was all taped up on both ends, and one of the springs was halfway sticking out one end of the box. My daughter was helping me get it assembled, and we had most of the frame in place, and were adding the short legs to it. Except we had 7 of the 8 connectors, and the last one wasn't in the box. It is a T shape, and has 1.5 inch square tubing, and 1.25 inch round tubing welded to the bottom, with a hole punched in the middle for a bolt to go through.



Similar to this one, I couldn't find an exact picture of the part, since the company website has drawings instead of pics on their replacement part ordering page. It is 3.5 inches across the square tubing, and just shy of 3.25 inches from the top of the square piece to the bottom of the round piece. The company I bought it from has ordered the replacement, but it is likely going to be a week or more before it gets here. I have an excited 7 year old who sees most of the frame put together and wants to jump, but I just can't finish it without this leg support. Would a hardware store have anything similar I could use in the meantime? I thought maybe in the fencing/decking area, but searching online I couldn't find anything but square to square connection sleeves and round to round connections.