Can I stop this action?

First, find out more about the action underlying the judgment: you can use the judgment number to look up the case with the court, either online (depending on how good or comprehensive your state court's website and online records are) or in person at the court clerk's office. (You need to look up with or at the court that issued this judgment, so if it is a judgment from another state, you'd need to try to look up with that state's courts.) 
Once you know what the case was (e.g. have the case's docket number, which is generally distinct from the judgment number), then you can look up how the judgement was issued against you--e.g. by default, if you have never responded to or appeared in the case. Then you want to look up the underlying court filings and get a copy of them, particularly the complaint (which is what they sued you for and why) and the proofs or affidavits of service (which is where they attested to when and where and how you supposedly received the court papers). 
Once you have all the above, you can see if you have grounds to make a motion to vacate or set aside the judgment, such as on grounds that they have the wrong information and sued the wrong person, or sued over a bill you had paid, or tried to serve you at the wrong address so you never got the complaint (not being properly served can be grounds to open up a judgment). 
If you don't have some viable defense to the charge or procedural ground (like improper or lack of service) to set aside the judgment, your best option may be to try to negotiate some settlement you can pay and live with. That could even be your best option anyway, since all vacating the judgment means typically is that now they have to sue you again (i.e. you don't win the case; you get a "do over"), and if it's valid debt, they will likely win.