Multi-Agent Systems are suitable to provide a framework that allows to perform collaborative processes in distributed environments. In a customer support system with operators attending incidences, the problem to solve is to find out the best solution for the problems reported to the system. Each operator can have its own view about which is the best solution in each case and thus, conflicts of opinion among agents arise. Therefore, to engage in an argumentation dialogue is a suitable way for a group of agents (representing operators) to obtain an agreement about the best solution to solve an incidence. In this paper, an argumentation framework for a Multi-Agent System applied to customer support is proposed to help agents to reach an agreement and jointly solve incidences.