bcrypt hash with salt

[Mem5]

What's your GPU card?
Do some math. Aasssuming you have a GTX 1080 Ti, you will try ~23'000 passwords per seconds.
You said "I don't know the length or characters used".
Assuming mixalpha+digits => 62 characters
62 at length 5 will take 11 hours to bruteforce. You can do it.
62 at length 6 will take 28 days to bruteforce. You still can do it..
62 at length 7 will take ~5 years to bruteforce. Good luck.

But brute-force is not feasible.

+1