I am a nurse working in the hospital.when my...

I am a nurse working in the hospital.when my previous manager resigned,they opened the post as Secondment as agreed for 6 months.I have applied,did the panel interview and i passed.since then for a year i had no increments or adjustment of the salary.As they say that secondment is a different way.but i work beyond the timeline of 6 mos.do i have the right to ask my employeer for the compensation?they did not let me sign anything for that role because they kept on saying its upto the management to decide..however for a year also i am seeking for clarification and direct answer but still no reply..