Supplier is asking to use content I made for my store of their product.

I have a supplier asking if they can use a video I made for an advertisement of their product that I sell.

I’m a little torn because on one hand – I currently use some of this supplier’s content on my website (with their permission), but on the other hand I feel like the supplier will use it to run ads as well (plus I put a lot of time in to it).

The supplier is already benefitting because we are pushing their products but since they also sell to consumers, I feel like I’m aiding a competitor.

Thoughts?