Doug
We're sorry that this mattress only measures 75-inches long. Can you tell us how long the mattress has been out of the packaging and if there has been any change to the size since you posted this review?
Since the mattress is shipped compressed, it will be a bit small when it is first opened. However, the Twin XL size should expand to measure 79 x 37.5 inches within 48-hours of being opened. If it is still smaller than this, then we will of course help you get a replacement or assist with a return to Home Depot.
Please email us at: cs@linenspa.com with more information and we will work with you to find a solution. We value you as a customer and care about your satisfaction.
Thanks!
-The Linenspa Crew