The Danish midfielder completed a move to Manchester United on Friday after penning a three-year contract at Old Trafford.
Eriksen joined the Bees during the January transfer window after leaving Inter Milan in the autumn following his cardiac arrest during last summer's European Championships.
During his time under Thomas Frank, the 30-year-old made 11 appearances, scoring one goal and creating four more to help the club to avoid relegation.
With some suggesting that Eriksen should have chosen to stay with Brentford through loyalty, former Chelsea man Cundy doesn't believe that the midfielder owes them anything.
Speaking on talkSPORT Drive, Cundy said: "He owes them nothing.
"I heard Simon Jordan banging on about this, he owes them nothing.
"They paid for his service, he delivered, his contract is up and he can do what he wants."
Cundy added: "Why didn't they give him an 18-month contract? There you go.
"They were tentative, they were a little bit wary and thinking that they didn't know what they were going to get.
"If he didn't deliver and he had a stinker, or he was injured for the whole time, do you think they'd want him back? You've got to look after yourself in this world."