I think Gibson will probably not for charge your card for the rest of monthly updates that no longer are coming. But if you already paid in full, I don't think they'll be returning any money they owe you since they don't have any. They are losing money so join the line.
Of course, we all should have know that paying in advance is a crap shoot, esp. in software. We took a chance, and hey, it didn't work out. Sad but true. Lifetime updates was too good to be true if you expected to be getting free updates 5 years into the future. 2-3 years was reasonable, considering users would have been ahead of simply paying by the year. Many paid $150 for about a year and a half, where Gibson comes out ahead. But not that much, if you were buying yearly updates. If you didn't regularly buy each year's "new SONAR," well, you were trying to get up one on Cake and Gibson.