I agree with the general consensus to fire them, but if by "senior" OP means 3-5 years and this is a junior with potential, people are so hard to find that I wo

I agree with the general consensus to fire them, but if by "senior" OP means 3-5 years and this is a junior with potential, people are so hard to find that I wouldn't worry about misleveling or the salary difference. But the key is someone with potential. If it's a mismatch, cut your losses.