Hi and welcome to the forum.
Either the 'servicing' hasnt kept the brakes free enough
The brakes don't receive any servicing; just a quick inspection to ensure there's enough meat on the pads and the discs aren't worn to oblivion.
What you've experienced is, sadly, all too common. Given the amount of salt used on UK roads, steel pads fitted into an unlubricated cast iron reaction frame are never going to work well for long.
Read
this thread to find out why this happens, and what can be done about it.
ECP will sell you a set of Pagid pads & discs today for about £57 including VAT. I've used these myself and they're good quality; certainly better than the OEM Fiat parts. Find a small independent garage to fit them; the job is straightforward enough that they could do a first class job for £50 and show a decent profit. Providing they clean & lubricate the reaction frames properly, they'll last you somewhere between 40,000 - 60,000 miles.
Take it to Fiat and you'll pay close to £300 (unless that £240 includes VAT) and be back where you started in another 20k. If they've already dismantled your brakes, you may have little choice but to pay up; they're not going let you take the car away without forking out almost as much for diagnostics and reassembly.
Don't even think about trying to make a warranty claim for this; brakes are a fair wear and tear item and you'll get nowhere.