Try to contact your customer as soon as you know you might be late. The more notice you give them, the more likely it is that they will be able to wait for you.
The customer’s contact number can be found on the Helpling Partner app in ‘More’ -> ‘Customers’. If you cannot reach the customer, make sure you drop them a follow up message. Try to do so via SMS and via app message to make sure they have received it.