Can someone please explain to me the difference between  Seni ozledim and Seni ozluyorum.

As I understand, Seni ozledim is ´I missed you´ (past) and

Seni Ozluyorum is ´I miss you´ (present/future). I am also told it is ok to use the past tense in the present...

Is this correct or not? I am very confused!!

özledim is past tense... 

you can use it in that case

you did not see or talk with someone. than you see/talk her/him. than you can say in past tense.

özlüyorum is, 

someone is faraway. and you can talk/write and you miss and continue to miss.. 

but also there is a usage.... you can say that, 

in day time i am always. ´özlüyorum´ 

it means, when i cant see you immediatelly i start to miss you.. 

fantastic explanation. Tesekkurler...