I have not help Mr.Wang send a package to Mr.Li by express so far.
问题描述：
I have not help Mr.Wang send a package to Mr.Li by express so far.
If I sent the package I will tell you tracking no.
中文背景是：
我没有帮王先生寄过给李先生的包裹.如果我寄了我会告诉你单号的.
答
时态,语法都有小问题.帮你大改了第一句,强调了重点.第二句,帮你改了时态和连词.
I have not sent the package to Mr.Li via EMS on behalf of Mr.Wang.
Once I send the package,I will let you know the tracking number.