and about this time they was through with the job and was ta

and about this time they was through with the job and was tapering off with a kind of general
thegood-bye cussing,问题是此句子中they was,应该是they were.为什么要用was啊?不是语法错误吗?They Was Holdin' Hands这是个书名,句子也是用了was.we/ you /they后都要接were.请给精讲一下.
with a kind of general good-bye cussing.上面写的有点错误了，多了个the。