Top Freezer working but Lower fridge isnt

Hi,

I have a SHARP Fridge brand and i traveled left it switched when i came back after a few months there was no power in the house found out the circuit breaker in the house tripped because of too much power cuts/fluctuations from the grid. I kept it back on and power was back in the house.

Now for all this time the fridge was off and alot of fruit flies/maggots were moving inside the fridge as food was rotten..i cleaned it but found out the freezer was getting cold but not cold enough and the fridge part at the bottom is almost warm not cool at all. i called the refrigeration engineer.. he came and mentioned abt some coil/capillary bring blocked and he added new gas.. but since he left the freezer is xold but the lower fridge is warm not cool. the fridge is a basic type not smart fridge.. the fans both work at the top and bottom..a friend told me the vents might be blocked. i wanst around but i believe the engineer must have checked and cleaned the vents


my question is if the vents are cleared what can cause the lower part to not cool??? because it's a basic fridge, the fans work both freezer end and lower fridge end, the freezer freezes. what could be stopping ?? could there be a sensor of some sort sonwwhere malfunctioned???