1995 Fiat Uno Complete power loss even when foot is flat on

Engine Performance problem
1995 Fiat Uno 4 cyl Front Wheel Drive Manual 100 00 miles

Hi

I recently did a service on my '95 uno fire, but when I got it back after a couple of weeks it was worked on, the carb was flooding. I had it reconed and it was fine for about 2 miles, and started backfiring/losing power and cut out completely, and wouldnt start again. They replaced a small metal (silver with 4 'pins') part on the distrubutor. Once again it was fine for about 2 miles and started 'shaking' back and forth again. It would accelerate for 2-3 seconds and then even with my foot flat on the accelerator it would not increase in speed but 'shake' back and forth like it was gonna stall/cut out completely dropping in revs kinda thing. At least it started again but I had to drive it back with my foot let going of the clutch and then pressing on the accelerator back and forth, obviously to keep the car from stalling. Please inform me on what the problem could be! I really am fedup and I'm getting 1000 different answers!
Thanks guys!