<human>: This is a throwaway because several people I work with read reddit. While they are generally good people, I want to protect myself.

Background: I work for a government contracting firm. I started off in a different department then I currently work in (I won't go into specifics, see above). 

The department I work in now requires that I travel often, which isn't that big of a deal for me. The issue is that while on travel I regularly work more then 40 hours a week, and the work is largely manual labor. While back in the office I do follow up work required for our travel. I am salary and get no compensation for this.

In October of last year we were having issues with one of our team members. Constant mistakes and inconsistent information were costing our project significant amounts of money. My project team at the time consisted of five people. The individual causing problems was in a completely different career field then mine, but myself and my co-worker agreed we could take on the responsibility and learn his tasking.

We spoke to our managers and clearly identified that we were willing and capable to do the trouble-maker's work, however we expected significant compensation for performing two separate job functions.

The managers agreed and said they would put us on a 90-day trial to see how we adapted to the processes and if we could manage the workload.

Fast forward to current: We were told for our annual review we would receive our compensation. They announced that our compensation would be 3.5%,  1% more then the company's average. Both my peer and I immediately voiced our issues with this. 

We both make under 50k a year, and felt that a 10k a year raise for performing the two job functions was a reasonable request. Our supervisor has now backed out of all his previous obligations and is scoffing at our request.

I'm not sure what to do, as they are not willing to meet our requests, and seem to think that we are now obligated to do both jobs and take the 3.5% raise.

Can you summarize the given text in a few sentences?
<bot>: I took on more job duties with the understanding that I would get a good raise. Time has come for the raise and company is lowballing me.