As it’s stated in the terms & conditions that order cancellation is not allowed after checking out, the outlet should inform customers that it’s not possible to cancel orders. 

The outlet should resolve the issue with the customer on a case-by-case basis if the latter disagrees. 

On cancellation in LLM portal:
If LLM order has been placed in <5min, we could still cancel from lalamove WEB.
If it’s >5min, we need to live chat LLM hence while doing that, call rider to inform the rider regarding the cancellation.