Hi, I’m not familiar with FlexPerks, but here’s how it generally works with frequent flier programs. If you’re looking to get frequent flier miles added to your account it depends on whether you’re trying to get credit for the miles that you’ve already flown, or for the miles you accumulated by charging the ticket on your credit card which has a frequent flier affiliation and may give you a certain amount of miles per dollar spent.
In order to get credit for the miles you’ve flown, you either had to a) enter in your frequent flier number when you purchased the ticket or when you checked in for your flight, or b) if you saved your boarding pass, you can contact the SkyMiles program and they will give you a fax number or mailing address where you can send in your boarding pass and they will credit the appropriate miles for your account. If you’ve lost your boarding pass, you may be out of luck, but it’s worth contacting the SkyMiles program over the phone, ask to talk with a supervisor, and see if there is still a way for them to enter the miles into your account.
If you’re talking about the miles that you earned on a SkyMiles credit card, that should be automatically entered into your account – you shouldn’t have to do anything. Hope this helps.