bad mood
Bad Mood

when I enter this company, there is a man who loves me at the first sight.
When I started working at this company, there was a man who fell in love with me at first sight.

But i really hate him.
But I really hate him.

I don't like the way he always follows me when I go with my collegues to have lunch or supper.
I don't like the way he always follows me when I go to have lunch or dinner with my co-workers. 

Even worse, he sometimes follows me when I finished my work.
Even worse, he sometimes follows me after work.  OR ...after I'm off work.

I have refused him deadly and I ask my friends to call me to pretend to be my boyfriend.
I have turned him down directly, and I ask my friends to call me, pretending to be my boyfriend. 

But the effect is not well.
But it hasn't worked. ( OR "but it has had no effect")

I want to solve this problem as soon as possible.
I want to solve this problem as soon as possible.

Bad mood

When I enter joined this company, there is was a man who fell in loves with me at the first sight. But I really hated him though. I don't didn't like the way he always follows followed me when I go went with my collegues to have lunch or supper. Even worse, he sometimes follows followed me when after I had finished my work. I have strongly refused him deadly and I even asked my friends to call me to pretend to be my boyfriend. But The effect consequences though is were not well good. I want to solve this problem as soon as possible.

Notes:
1. You must use capital letters at the beginning of a sentence in English. They are not optional.
2. You are talking here about the past so you must use past tense, not present.
3. You cannot start a sentence with "but".