I don't have experience with Doblo's keyfobs, but I was struggling with a 2011/12 Ducato keyfob and previously with an Alfa Romeo one.
You have 2 possibilities: the microswitch is damaged (so it can't send the signal) or the rubber is damaged (so you can't reach the microswitch). Dismantle the keyfob, check by pressing directly on the microswitch to confirm if it's working. Be sure the battery contacts touch the pcb if the battery is not on the pcb itself (2 versions were available).
If the microswitch is working, find a new keyfob. Original parts are best, aliexpress sells crap. Even silca is now producing in China, the quality dropped significantly
If the microswith isn't working, check the type of the microswith on the pcb of the damaged keyfob. Order new microswitches (all of them, they are very cheap), replace with the new ones (you'll need to solder them).
It's the cheapest and best solution.
The pcb of my Ducato is a Magneti Marelli product. Still some three years ago it was possible to buy the original pcb, which was ready to be programmed in
MES. They are no longer available. At least in Europe.
Locksmiths have the proper tools to program the PCB. But it costs money.
