I don't know whether any state refused to return a fugitive slave from South Carolina to his/her owners. That might take some searching to find. But I did find where a fugitive slave from South Carolina who escaped to Massachusetts decided to flee to Canada after the passage of the 1850 fugitive slave law. He was aided in that escape by Harriet Beecher Stowe who sheltered him and gave him refuge, food, clothes, and money in his escape to Canada. So, Harriet Beecher Stowe could have been fined and jailed by the 1850 law had her actions been discovered.
This incident was mentioned on page 36 of the book The Experience of a Slave in South Carolina by the escaped slave John Andrew Johnson.
Of course, the later Massachusetts personal liberty law made it more expensive to recover a fugitive slave than the slave was worth. So if any South Carolina slave escaped to Massachusetts after that law was passed, he or she was essentially free through the actions of the state of Massachusetts. The last fugitive slave returned to his/her owner from Massachusetts was in 1854.
This one shining example of a fugitive slave, John Andrew Jackson, who escaped from South Carolina sometime in the 1840s(!) and then to Canada after the 1850 Fugitive Slave Act, is somehow justification for South Carolina Slave-Holders to declare secession in December of 1860?
I don't think so.