Ringtone vanished

I recently purchased a ringtone for my new to me BB 9530 and set it as the default. It worked fine for a couple weeks but this morning when my phone rang, I heard the standard default ringtone. Upon investigating this, I found that the ringtone I purchased is no longer on the list of tones.

Why would this happen and can I retrieve the ringtone without having to pay for it again?

Thanks in advance for any help!!