I would consider getting a second opinion
Did your mechanic hook up an external oil pressure gauge and take a reading?
Does the engine have the proper oil level?
Does the engine no longer start?
Or does it start, but it’s making awful noises?
FWIW . . . the oil pump itself is usually not the cause of low oil pressure
What engine in this vibe?
I think your mechanic . . . or another mechanic . . . should be able to locate a relatively cheap used engine and install it
A Vibe is essentially a rebadged Toyota Matrix, which is generally a very reliable car
I would not give up on this car just yet, if the rest of the car is in good condition
Assuming your car just got out of the body shop, I’ll assume it’s pretty straight. How about rust?