Always good to hear feedback - thank you for sharing. The speeds you experienced are indeed on the low side, but several factors are important here; speed tests are not always reliable, so I usually ask whether certain apps/sites did not work as they should. 190kb/s down and 120kb/s up should be fine for most web based applications, but clearly won't feel as speedy as on a residential or business connection. Try to avoid using the speed test results as the sole guidance for whether the connection was usable.
In many cases, computers have stuff running in the background that slows things down (think Dropbox, Windows Update, Adobe Updater) or other data hungry apps. Always try and disable those when possible.
Since bandwidth is shared, the available connection is of course shared between all users . Also, in most cases, speeds will pick up pretty quickly. The start of a flight is usually busier than an hour or so into the flight.
I'll also drop my colleague at customer care a note asking to check why you did not receive your service credit - these are automated, so there is no reason why it did not go out.