You've got a Seneca and externally it looks nice. Don't know about the others here, but it's close to a Grail Gun for me. Sounds like it's only going to cost you $200. So, in my book, you did good.
If the refund comes through, have it relined. I'd go with 36 and use whatever twist rate TC used. Then shoot the heck out of it with 20 gr loads and PRB. I have a 36 Seneca and it's the perfect small game and target rifle. Fun, cheap to shoot and danged accurate. Keep the loads light and it'll shoot all day without swabbing.
Don't try to make it into something it's not...a deer rifle. It's too delicate for that, yet with some care it'll last a lifetime and more. Bob Hoyt's barrels shoot; if they don't he'll make them shoot.
When all is said and done, you won't have gone much past the $400 you originally paid for the rifle.