Check the manufacturer's website.
Many times a company will list where to find their products directly on the site. They may even link to an online location to buy their products. At the very least, you will be able to see what the refill packaging looks like to give you a better chance of finding it at your local store.
Check a local store.
Larger local stores will usually begin receiving shipments of refills at least within a few weeks after the product debuts. Try looking at a store, that carries a large selection of cleaning products, or at a retailer that carries the brand of product you are searching for. Remember that the refills may not be stocked exactly next to starter kits for the product. Scan the shelves to find what you need.
Ask for help.
Ask an employee if the store carries the product. If they don't know, or you feel they don't know, politely ask to speak to a manager. You have a right to get good information. Chances are you won't be the last to ask.
Ask them to carry the product.
If the information you get, is that they don't stock your refills, tell the manager that you want them to. All stores want to carry products that consumers want to buy. Your voice could start a chain reaction.
Call the company.
Consumer helplines are there to serve the customer. Call and let them know that despite your great interest in purchasing refills for their product, nobody will sell them to you. Ask them what can be done.
If all else fails, remember that sometimes even good products are discontinued or not profitable. If you can't get the refills, research products that may get the same job done.