basically it sounds like the nozzle is too close to the printbed.
so calibrate it.
Use a sheet of decent printer paper (90gsm is ideal) and have it so that the paper slides between the bed and the nozzle and just catches.
So you can feel a little friction but it mustn't be tight.

I would also recommend replacing the levelling knobs with knobs that have a nylock locking nut embedded. That way - once levelled - it will STAY levelled.

the a8 is actually a full Prusa design i3. so with a few modifications can be a really nice machine.