Help please,

Few days ago we packed ourselves heading for a seaside and all of a sudden my Jazz GD 1.4, 2003, cranks normally but wont start. I tried a few times more and I noticed that there is no sound of fuel pump when I turn the key. I went to a mechanic, a diagnostic tool showed 2 errors: P0339 Crankshaft position Sensor A circuit intermittent and P0035 Crankshaft position Sensor A circuit. After 2 days of searching for a culprit they called me and told me that they have changed the Crankshaft position sensor with a new one, but nothing has changed. The car still cranks but won't start. Just to mention that the car has not given me any signs of this recently, worked completely normal urban and on a highways, except on one occasion, maybe a month ago it stalled when I was closing to roundabout (30km/h speed) but it started right away. Now my car is towed to a electrician because previous mechanic told me that for now on it is an "electric issue".
Hes someone experienced anything similar?
Could this be an issue with a bad fuel pump (my first guess) or even with aftermarket alarm (my second guess)?
Please help, I am desperate....