No excuse at all for that shoddy work. I have accepted tanks from other manufacturers a couple of times that weren't exactly what I ordered, and I always thought about it every time I looked at them. Grrrrrrrrrr! One of them failed too! Double GRRRRRRRR!
You have all the leverage in this situation. I assume you paid by credit card? Lots of leverage there. If they didn't deliver as ordered, require them to make it right or file a claim with the credit card company.
To give them some incentive to work with you we may be able to work together. I am looking for a cheap (i.e. ugly or old) tank for outdoor use. As long as it holds water, tell Tenecor they can make a deal with me on your tank (which you should refuse and get what you ordered). Perhaps if they know they have a buyer they'll cut you a better deal. I'd pay wholesale cost plus shipping.
Just a thought!