If they take phone orders you could just play a pre recorded messages and call them using twillo. I've done this in the past to call many stores and check inventory of an item
How does this work with a conversation? Did you ask them to press 1 if the item is in stock, or send you an email to a provided address?
You could start the message by explaining your situation. But yeah still lots of edge cases this doesn't catch.
Twilio has different verbs you can use to quickly and easily throw together a small voice controlled phone tree with basic conversational understanding.