Hi @Anonymous User
It is possible to reach your device limit if, for example, you've had all four slots filled in the past and then delete one or more to make space. You are then allowed to only add one device each month. The following article explains the device limit rules
http://help.nowtv.com/article/Device-limit-reachedHowever don't worry, when a member of the NOW TV Team pick up your message they can look into it for you and should be able to reset your devices so you can use your PS3 again. Just wait for them to contact you on here.