We asked OS Ticket and they replier we had to pay for their help.
Well, if I have to pay because there is a bug in the system, this is no open source :-)
From what address did you download your osTicket installation package and where did ask for support?! Just asking because this sounds like someone tried to scam you and is not the correct contact person / support for osTicket, since they would not want you to pay for that!
First, the correct osTicket web page, github repository and so on:http://www.osticket.com/http://www.osticket.com/downloadhttps://github.com/osTicket
Next, let me answer your question with the tickets. It sounds like you forgot to setup a cron job / scheduled task to import the mails into the osTicket system. Therefore see the osTicket wiki:
http://osticket.com/wiki/POP3/IMAP_Setting_Guidehttp://osticket.com/wiki/Email_Pipinghttp://osticket.com/wiki/Email_settings