thz for ur help/helping

1. thanks for your help ---------It is correct and is commonly used.
2. thanks for your helping------It is also correct because HELPING is a gerund in this sentence. If you want to describe in details for HELPING, e.g. thanks for your helping my sister over the homework., the word HELPING as a gerund should be used.

which one is correct?
1. thz for ur help-->Thanks for your help (it is correct!)
why?
help (noun)-1. 幫助, 2. 幫手,助手
Your (pron.)-你的;你們的
Your 後應跟help (noun)，唔係help (verb)!!!
2.thz for your helping (it is incorrect!)
why?
helping-help (verb)
Your 後應跟help (verb)->grammar有問題!