Keypad is difficult to use with tmobile voicemail

Inputting the TMobile voicemail PIN from the dialer-app is possible, but quite difficult. Voicemail for TMobile can be accessed by dialing '123' or by dialing '18056377243', so I created a contact for it. From the Contacts app, I can call it, and the voicemail system says "Please enter your password, then press pound". If I enter the password too quickly, then the voicemail system tells me I entered the wrong password, with missing digits (eg, if my password is '1234' and I enter '1234#' quickly, the voicemail system might say "Sorry, '1' '4' is not a valid password...". It seems for best results, I need to wait til after the voicemail system says "... then press pound" and then enter the PIN digits at a rate of something slightly faster than 1 digit per second.

Honestly, it took me so long to figure out the timing that I thought accessing voicemail from my phone was not possible. Perhaps this is related to bug #1122584, where TMobile Visual Voicemail needs to be implemented, but it isn't clear to me if the dialer-app simply skipped some or sent them too fast. Perhaps the dialer-app could queue all the presses, then send them in a uniform fashion to ensure the other end gets the selection correctly.