The Bee Network was launched in the south of Greater Manchester in January - meaning the whole region now has a publicly-run bus system.
The 203 service was previously operated by Stagecoach and is used by mums to take their children to school in the Reddish area of Stockport.
Stephanie Conwell uses the 203 bus to take her son to Abbingdon Primary School in Reddish.
"It's been absolutely horrific since the Bee Network was launched. We're never at school on time. It is costing me £20 a week and I've had to use taxis," she said.
"Everything was great with Stagecoach. The buses always turned up."