Cory Environmental has apologised to Cornwall residents after complaints that rubbish was being left on streets.
Cornwall Council said it received more than 38,000 waste-related calls in two weeks after Cory took on the collection contract at the start of April.
Residents of Summers Street, Lostwithiel, told the Cornish Guardian they were forced to weave in and out of rubbish for more than two weeks after being missed by the service.
Cory Environmental general manager Nigel Carr said smaller vehicles were being brought in to areas where narrow lanes had restricted access.
“We apologise to any resident who has had a missed collection or experienced disruption to the service during this major change,” he said.
“We have brought in additional vehicles and staff to help deal with missed collections and deliver the remaining recycling containers.”
Council portfolio holder Julian German branded the level of missed collections “unacceptable”.
“This has been a massive change affecting every single household in Cornwall,”he said.
“While we had anticipated that there would be some initial teething problems, it is clear the implementation of the new contract in some parts of Cornwall has not been satisfactory and we are taking this up with the contractor so that problems are resolved quickly.”