When they say they get speeds of 28 k/sec they mean a throughput of 28 kilo
bits not Kilo
bytes.
Roughly, if you divide the 28 kilo
bits by 8 you will get how many Kilo
bytes....about 3.5, so don't worry, you are in the same speed range.
In my case, with high speed ADSL I get 3 mega
bits throughput or roughly translated that's about a download speed of 375 Kilo
bytes/sec.