First, I practice in Colorado and not in Texas and I'm not your attorney, so this is intended as general advice and I would suggest you contact a Texas attorney if you determine you need one. However, you posted this in a Colorado forum. So I'm assuming you're in Colorado.

Second, this is very generalized advice since you've not provided what I consider to be important information. It's probably not possible to give all of the details a lawyer would need to give specific advice. For instance, some of the information needed would likely be elicited from these and other questions and follow-up questions: Is this a delay related to the COVID-19 pandemic? Is this unrelated to the pandemic? Was this an online purchase, by mail-order catalog (yes those still exist), by phone? Is there a long-term relationship between buyer and seller and if so are there terms that are implied by the relationship? What are the exact terms of the sale? What is the value of the sale?

Assuming you are not getting a full refund and the seller is unable to meet the order, you could consider contacting the Colorado and Texas Attorneys General, as this retailer's actions may affect others, as well.

If it's not that type of inquiry--involving something that an Attorney General would be able to help with--you may need to consider hiring a lawyer to write a letter to the retailer. In business, sometimes these decisions turn on the value of the transaction--for instance, the buyer may just give up if it's a stick of gum that wasn't delivered. And on the other end of the spectrum, if your space shuttle wasn't delivered you'd want to hire a lawyer even if you had to pay hourly for their help. Depending on the value, some lawyers may consider a contingent fee or a mixed hourly/contingent fee model to try to help you but to keep your out-of-pocket costs down.