It would help if you bought a universal remote. Those work the best in every situation, and your fit perfectly. You can take a look at
https://doorsdirect2u.co.uk/product-category/garage-doors/ to see what's good for you. I don't understand how it didn't come with a remote. It never happened to me. Maybe speaking with the dealer is a good idea too. They must've simply forgotten about it. Either way, it's no big deal! Installing a universal remote is very easy and doesn't take very long. Also, it's not expensive at all