Mechanical advice

So I have a 2010 Versa that I took in to my local Nissan to have a fuel pump replaced. They also replaced a control arm as well. Upon getting the car back I'm having major issues with the brakes, after driving it about 30 miles the brake fluid was completely gone and the brake pedal was going all the way to the floor, I bought some more brake fluid and filled it up everything was fine, about a hour later it needed more brake fluid so all in all I have put probably close to 42 oz of brake fluid which seems like a lot. I took the car back in to the service center, my question is how likely is it that the service center messed something up while working on my car? I did not have this issue before the car went in. The service center waived the diagnosis fee but they were the only ones under the hood and this happened almost immediately after getting the car back from them. I'm still waiting on their diagnosis but they were trying to tell me that nothing they repaired (fuel pump, control arm) had any thing to do with the brakes, but I find it fishy I'm having a whole new issue with the car immediately after getting it back from the service center. Any advice on how to proceed with them would be great.