Union leaders, who put a black ribbon under the plaque bearing the HT sign, warned that this was the second change of the company's name since Deutsche Telekom (DT) became its strategic partner.
The change of HT's name is happening simultaneously with downsizing, and the 18 million euros would be enough to pay two-year salaries of 700 workers who will be laid off by the end of the year, union leader Jadranko Vehar said.
He added that the union would organise a referendum in ten days' time to decide on a day-long warning strike, which is expected to take place on October 26.
The union demands that the problem of surplus labour be solved the same way as it was solved in DT, by reducing working hours from 40 to 36 hours a week and by forming employment agencies in HT, which would find employment for surplus labour.
If the warning strike yields no results, the union is prepared to organise a general strike on November 16, which would last until the workers' demands are met.