Alert events are gone

Hey everyone ..I do not know if I am the only one wit this topic. It turns out that every single month I generate reports of our data links, of course if the graph reports 95% of availability, it has to match with the DB alarm for that link...well ...I week ago had to deal with a link failure, I got the e-mail from opmanager telling me about that, I checked the db alarms and the event was there....today while trying to generate our monthly statistics the graph reported 100% of availability for the link with the failure. I checked the DB alarms and all had gone without a reason. Of course, now I have an inaccurate report.

can somebody tell me if there`s a way to get the alarms back in order to have a correct availability report ?

Thank you