Regular expression matching a new line

I have written a script to test some isdn links in my network and I am trying to format the output to be more readable. Each line of the output has a different number of digits as follows...

Sitename , spid1 12345678901234 1234567890 1234567 , spid2 1234567890 1234567890 1234567
Sitename , spid1 12345678901234 1234567890 , spid2 12345678901234 1234567890

I would like to drop any string of either 7 or 10 digits and keep ony the 14 digit strings. I have attemted the following command but it gives me an error "Invalid preceding regular expression"

sed 's/\<[0-9]\>\{7,10\}//g' oldfile > newfile

Can anyone point me in the right direction to format this file? Thank you for the assistance.

Change the word/number boundary indicator to take in more numbers.

sed -e 's#\<[0-9]\{7\}\>##g' -e 's#\<[0-9]\{10\}\>##g'

or

sed 's/\<[0-9]\{7,10\}\>//g'