No memory after going into recovery mode. I received a message (enter usb2.0 msd mode (what does this mean). Anyway I removed the usb connection and it read, safe to remove usb upgrade complete, but the memory was lost. the memory was also removed why? What can I do to correct this problem

i hav had this mp3 player for about 4 months after exchanging it once. it know tells me that i have bad tracks on the device and i deleted all dsongs off of it yet they were still on the mp3 when i turned it back on afterwards. and the newest problem i have encountered is that i used to have about 900 songs on it but ever since the bad track incident i havnt been able to put more than 200 on it...like i lost memory on it....any help would be appreciated before i smash this mp3 :) thanks i hav had this mp3 player for about 4 months after exchanging it once. it know tells me that i have bad tracks on the device and i deleted all dsongs off of it yet they were still on the mp3 when i turned it back on afterwards. and the newest problem i have encountered is that i used to have about 900 songs on it but ever since the bad track incident i havnt been able to put more than 200 on it...like i lost memory on it....any help would be appreciated before i smash this mp3 :) thanks