Postgres not vacuuming 1 table
First, take a long, careful look at Aggressive Autovacuum on PostgreSQL as it may very well describe your problem, and check pg_locks to see if there is a locking issue on the table (there may well be one) and also look carefully at Josh Berkus's recommended autovacuum settings for aggressively autovacuuming.

To recover from a bloated table you can run the cluster command from psql (exclusively locks a table, but much faster than vacuum full). 

Third, if this is a locking issue, you may try to use a cron job to run a vacuum or even vacuum full (or cluster) during low-utilization times.