Throttling

Im pretty sure my service has and is currently being throttled.  I have a chat transcript that proves this.  The lady tells me that I'm at 267gb (cap is 250gb) and its probably the reason why my signal kept dropping.  I then asked if this is whats called data throttling, a long pause then comes back with "please allow me a minute".  Then  says that Cox does not do this.  

So let me get this straight.  Ive had the service 4 months, never had a problem (never went over either).  Then I go over 2 days ago all of a sudden it kept dropping the connection.  Its frustrating, and I need to know if there is a law against this.