How do you track customer satisfaction for last-mile delivery services?

For last-mile specifically, we've had good results with a short post-delivery SMS survey (3 questions max) triggered within 2 hours of confirmed delivery — response rates are way higher than email. Track CSAT on delivery experience separately from product satisfaction so you can actually isolate the issue. If your delivery scores are fine but overall sat is low, that's a pretty clear signal the problem is upstream.