In case you want to stop receiving messages on WhatsApp, what you can do is block and report the number directly in the messaging app, leaving the spam option, as the reason why you do not want to continue receiving these types of messages.
Why does Rappi send SMS messages?
When you register in the application you accept the terms and conditions of the delivery company, which indicates that they can send advertising messages to your phone number. This means that Rappi registers your account and associates it with your phone number, which is replicated with other apps.
Now, in case you have followed the steps to cancel or deactivate Rappi messages and the app continues to send you advertising messages, you can contact the company through its website, to cancel.
Many users think that just by deleting the Rappi application they will stop receiving these messages, however what you must delete is the link of your phone number with the app.
In case it is not only the Rappi app that sends you messages, what you can do is check the permissions you have granted in your applications to avoid advertising spam.