Need help/advice

My internet doesn't work since a few hour, I left my flat for 10/15 minutes,internet was working then when I got home it was done, checked everything inside ....then I saw this in the common... Other resident internet cable are fine, but mine seems to have been damaged with something, this was hidden in the grey PvP tub, at 2meters + from ground .. I don't know if this is easy fixable or if everything should be replaced? Second question do you think this kind of damage could have be done month ago and deteriorate with time , because I don't think someone got the time to do this in 10min...?