Collections

I've been contacted by Protocol Recovery about a cc debt I owe. They were the typical threatening agency. We came to a payment agreement. I asked for something in writing via email. They said OK. I never received anything. The calls started again. I told PRS I never got anything from them. They threatened a lawsuit. I was told that a "strange person" showed up at my work looking for me a couple of days ago. (I'm out of town). I was told about a month ago that a similar person shoiwed up at my home. I do not live there since I'm in the middle of a divorce. The person did not I'd himself, only had papers for me. I want to work something out but not like this. Can I trust PRS? Any ideas? Don't know if the TX SOL pertains to this Don't want to go to court over this as the divorce is bad enough. Thanks