I've since 1 month a vps and i've 2 Problems.

Last week I've a crash and after a restart all is working well except for the Pop3 server:
-> POP3 server unavailable. Maybe POP3 service is down at the moment.
I use a vps with Debian and Confixx 3 pro. I'm a newbie with vps, Linux, etc.
How can I restart the Pop3 Service?

My second problem are with the size, it grow, grow, and grow and I dont know waht I can do to reduce the size of temp file and I dont wish to run out of space ;o(
What should I delete? Wich files and where? How can I make a cronjob to do that?
I read in this forum on lorotate, what it is? Is this function no automatic implemented on a vps?
My host are not so good as I think and plan to change next years, but at his time, I must do it by myself.
I hope you can help me.