A Listing package price changed to "Available" text

Hello,
One of my listing packages suddenly changes the price number to "Available" text (see screenshots). Recently, I have installed a new payment gateway plugin (not Flynax's) so I'm not sure if it causes the problem or not.
Actual results:
- When I add new listing, this broken package will be selected automatically.
- The price is appearing correctly in the backend.
- When submit a listing with this package, it won't go through payment process.
- Now when create a new package, it doesn't appear in frontend.

Anyone knows what's going wrong? Please help. I took the whole day for investigation but no luck.

Thanks.

Attachment 3582

What payment gateway are you using? Can I see the link to the problem?

I'm using a homegrown plugin made for a domestic pmt gateway.