Dynacord PowerMate 1000-3 mesa de mezclas

I recently purchased a Dynacord PowerMate 3 online from Bax Music. Unfortunately, I encountered a serious problem with the internal effects.
The FX1 and FX2 do not work correctly when changing programs. Even though the display shows that the program has been changed (for example from 5-55 to 5-59 or from bank 5 to bank 6), the effects immediately return to the default program 5-55. The screen indicates a change, but the sound does not follow.
At first, I thought the unit was defective, so I returned it. Today, I received a brand new replacement unit, which I tested together with the staff in the Bax Music store. Unfortunately, the exact same problem occurred on the new unit as well.
Because this issue happens on multiple units and directly affects live use, I cannot rely on this mixer for professional work. For this reason, I do not recommend this product.