In my experience, if you REALLY do your research and you produce, in writing (letter or email), a decent justification why you would like to have a different pump to the ones that they already offer, then you probably find that your team are very receptive.
My team were offering 5x different pumps when it came time for me to have a pump (my first).
I wanted a patch pump, but i take about 140 units a day, so that would not work.
So, i spent ages reading forums, manufactures sites, YouTube vlogs and speaking to other people who actually had the pumps.
I found that i wanted a Tandem t:slim x2.
I made my case, and even justified why they should remove 3 of the other choices (they were out of date and had been replaced with newer models).
They agreed, and my consultant said it was refreshing to have a patient that made her job easier rather than just "asking for more choice".
I can't guarantee that this will work for you, but if nothing else you will convince them that you are serious about what you want.
Good Luck