I received a judgement letter from Mann and Bracken in regards to a bill I incurred with Jcpenney. I have been making monthly payments to Mann and Bracken but I have not been able to make the amounts they require to close out this acccount. My question is if I am making some kind of payment on this account can Mann and Bracken garnish my wages or send a police to my job to collect the balance on the account. Thanks in advance

Well first unless you live in some place like china I doubt the police will be coming to your work place to collect money.
If they have a judgement, they may garnish your wages anytime they wish, unless your payment plan is in writing. If you have a written plan, and you make those payments, you have a defense. If you are just paying them and only paying what you want, and there is no formal agreement, yes they may garnish you if they want ** assuming it is legal to garnish in your state.