The diner has an issue with the order. What can I do? Abigail Marchione Updated October 23, 2018 04:43 Follow Advise the diner to call into Grubhub Customer Care at 877-585-1085. Customer Care will help them sort out the issue. After letting the diner know to contact Customer Care, move onto the next delivery. Related articles I need to reassign an order I’ve accepted. What can I do? Someone else picked up my order at the restaurant. What can I do? I’ve accepted an order that is already late. What can I do? What should I bring with me on deliveries? Where should I start my block? Comments 0 comments Article is closed for comments.