This literally just happened to me last week. I emailed them to ask them how to stop this:
> I understand you want to opt out of all points and rewards and not be tracked.
>
> We're constantly working to make Bilt as rewarding as possible. Currently, we don't have an option to opt out of points or rewards. To prevent your transactions from being tracked, the most effective step is to unlink your card from your Bilt account.
>
> To unlink the card:
>
> Go to the Wallet tab > Scroll down to the Your Linked Cards section.
> Look for the card you would like to unlink and tap View all benefits.
> Click the ellipsis [:] on the top right, then tap Edit > Unlink.
Gah, I hate this service and will avoid renting on buildings that use it in the future.