Lack of service

For the past 3 months i have been attempting to get hold of a payroll person at Excellerate Security Services using contact no 0860110011. Someone answers and i ask to be put through to payroll department, nobody answers because the voice message says nobody at this extension must leave a voice message and then after 2 seconds get another message saying the mailbox is full cant take anymore message, does not matter what time of the day i phone. This is unacceptable, can i be provided with a working number in order to address my concerned.