how long will i get free CDs from Ubuntu?

[丁昱]

I am in China,and I have downloaded ubuntu 7.04 for more than three
times.However, when i burned the iso file into cd,it did not
work.First,I doubt it is cause of my combo driver.But,when i used MD5
check software,i found it is because the error rate of transfering
bits.ISO file wouldn't work if any bit is wrongly changed when
transferring.I have requested free cds from ubuntu.How long will it
take for me to receive it?
Will it be ten-week long?Hopefully as fast as I hope.I used to use
debian and fedora core.Debian's net installation is good.Hope ubuntu
can put forward such action.