I have an old T-Stick that I don't really use anymore. Back in the day, I thought I would use it more in future so I usually top it up $10 each year to keep it active and not lose the accumulated credit (about $90 now).

I have two (related) queries:

 

 

1. As I said, I have about $90 credit. Is it still the case that topping it up $10 will extend the validity of the credit, as well as the account? Or does the credit expire after 12 months regardless? The T&Cs are less than clear about this point, in my opinion. They imply that the credit expires, but that hasn't been my experience for the last 5 years (at least).
2. What else can I use the credit for, if I'm no longer using the T-Stick (it expires next week if the $10 topup doesn't work)? I toyed with the idea of selling it with the credit but don't know what kind of conversion rate I could expect. Would someone give me $100 for $101 credit plus the T-Stick? The only other thing I thought of was putting the sim in a phone and using it to pay for parking. Any other ideas?