Re: Greetings from Southern California
A few years ago I worked at a Motorized Bicycle shop here in Tucson building and repairing motorized bicycles.
I cannot count the number of new kits I opened to find missing parts. I know your frustration at least you got your missing parts replaced, we never did.
The rear sprocket can be a pain, but with patience and practice you can get it right. Before you know it you can mount a dozen rear sprockets in a day with no problems.