My employer will be paying a stipend each month to offset health insurance I already have in place. I had a probation period of 90 day, I have been here for almost 11 months with no money paid. I have approached them about it and now they say they will no

My employer will be paying a stipend each month to offset health insurance I already have in place. I had a probation period of 90 day, I have been here for almost 11 months with no money paid. I have approached them about it and now they say they will not pay the money for my 90 probation period, which I think should be included since they kept me as an employee. There is no language in the job offer that said the stipend would not include the 90 days. I worked those 90 days and did my part. Who is correct?