Can an employee on long term disability receive a cost-of-living increase?

Employer's sponsored long term disability plan is now giving employees annually cost-of-living increases. During the time I became disabled the plan didn't have cost-of-living increases and now they do and I was told that I didn't qualify because when I became disabled they had no mention of cost-of-living increases in their plan. Employer follows the Social Security Administration polices. SSA gives disabled cost-of-living increases.