Looking on the internet deeply has found these results:

I have not see you for a long time is the most popular phrase on the web.

I have not seing you in a long time 10 results on the web	I have not see you for a long time 13 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	2013?2?26? ... Dear mike: I have not see you for a long time.Please let me tell you a thing. Today ,we visted a farm.Early in the morning we met at the school�... 2014?5?14? ... Dear mike:I have not see you for a long time.Please let me tell you a thing. Today, we visted a farm.Early in the morning we met at the school�... I have not see you for a long time ))) I hope you doing well and Thanks� Hi Kellie ,how are you ? I have not see you for a long time ))) I hope you doing well and�...

I have not seing you in a long time

10 results on the web

I have not see you for a long time

13 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

2013?2?26? ... Dear mike: I have not see you for a long time.Please let me tell you a thing. Today ,we visted a farm.Early in the morning we met at the school�...
2014?5?14? ... Dear mike:I have not see you for a long time.Please let me tell you a thing. Today, we visted a farm.Early in the morning we met at the school�...
I have not see you for a long time ))) I hope you doing well and Thanks� Hi Kellie ,how are you ? I have not see you for a long time ))) I hope you doing well and�...