Here’s what consumers have asked with answers from InterPals.net staff and previous consumers.
If your account was suspended, you can't reactivate it. You need to sign up for a new one.
Usually what's happened is that the person who sent the message has either deleted their account (or, very occasionally, had their account suspended) in the time between them sending the message and you reading it. There's nothing you can do about it unless they create a new account and choose to message you again.