Sometimes we Deafies can get frustrated with the communication break down between the hearing. I would certainly hope that they are at least seeing you are putting forth an effort. Either way, it gets frustrating for both parties... as I'm sure you can see. As DeafDucky suggested, texting seems like a pretty good temporary solution for the time being, even if you are in the same room. The fact that you are wanting to learn some ASL to me shows you are putting effort into making your work environment an equal one, and I admire and respect that. The previous suggestion was also to see if they would help you out with a few signs. I know back Pre-C.I. days for me, I was always more than willing to help a coworker learn a few signs who was genuinely interested for the sake of communication and learning. ( I still will help someone out, it's just not as needed now even though I still use ASL outside of work... I don't use it inside of work as much unless a patient needs it or I'm speaking to another coworker )
As previously stated by Reba, I do hope you eventually follow up with some learning, but this would be a good chance for them to throw you a bone so to speak and help you out a bit. It's clear you're wanting to help them out, they should definitely be willing to meet you half way.
Coming from our point of view though... Writing things down. Most of the time, when we explain to people we're Deaf... a lot of peoples first reaction is to tell us to write things down... without listening to us, without hearing us out... without giving us a chance, to hear or attempt to understand us. A lot of us don't have the voices of angels... we're WELL aware of this... Some of us are lucky enough to have had Voc therapy... ( And when we have or do have Voc therapy, it's not like once or twice, you go FOREVER and keep going FOREVER... it's not easy to not be able to hear yourself and form words that sound "normal" ) some of us not... but sure, some of us aren't easy to understand... it's the majority of people making absolutely ZERO effort to understand and within .0001 seconds of finding out we're Deaf throwing a pen and paper at us. That is the negative paper / pen reaction you're getting... it gets old. So that's my take on it. I have an INCREDIBLY clear voice ( ages of voc therapy ) and have STILL had people hand me a friggin pen and paper seconds after explaining that I am Deaf... Yeah, it gets pretty infuriating... Can't tell you how many people I've almost made eat that paper and stabbed with that pen....
Regardless if you're trying to understand... if they don't feel you're REALLY trying to understand them speaking... of course you're going to get the "omg he's handing me paper" death fire look... it's absolutely infuriating and p***es you off more than I can possibly describe. It would be like every time you talked someone handed you a pen and piece of paper to reply... They wouldn't listen to you say it back, you could only write it down.... You would absolutely snap... Same difference essentially... kind of... you get what I'm saying or where I'm going... it really just burns your biscuits... I'm getting hot just thinking about it really....
I do believe you're sincere, I'm just trying to show you why they would be upset and where they're possibly coming from, that's all. The texting suggestion is a good start, and like it was also suggested, maybe ask them to show you a few signs and that will show them you're really interested and trying.
Good luck.