Is it permissible to give a sum of money to a technician from the postal company in exchange for delivering internet lines and receiving prompt services should the line be disconnected or a malfunction occur?

The amount paid to the technician is a forbidden bribe because it is given to him to perform his obligatory work. It is a bribe that is forbidden to give and to take, due to the hadith: "Allah has cursed the one who gives bribes and the one who takes them." However, if it is impossible to secure one's right from the worker except by paying a bribe, then there is no sin in paying it, and the sin falls upon him (the one who takes it) not on the one who pays it.