How to phrase an email dropping a client?

[KanyesVest]

I posted a while back about wanting to break up with a client. I finally had a chat with them in Nov, essentially to give 6 weeks' notice (our agreement was 4). They asked me to reconsider (I provide a key function for them) and we discussed some very outline/provisional alternatives. My contact discussed this with his wider team in early Dec. I've heard nothing since. Frankly I'm pissed off. I would have considered different terms, but since they haven't even given me an update on where they are in their thinking, I just want to make the break. All that said, I don't want to burn bridges either. I've never broken up with a client before, and since I've tried the "it's not me it's you" line, could anyone suggest any edits to what's below?

Dear xx

I hope you had a nice Christmas break. As we discussed in November, I am no longer in a position to provide the ongoing service as [role] for [organization] and as such will finish on 31 January 2016. I have enjoyed working with [team] and as I mentioned when we discussed this before, I would be happy to discuss any project based needs [organisation] may have where my experience my be able to support your work.

Best wishes,
Kanye

What contact has there been inbetween?

Personally if I hadn't heard back I would assume that the contract ended at the 6 weeks notice period.

There was an update meeting in early Dec, Doreen, the last part of which was the team discussion about my whether they wanted to review my contract or if I'd just finish up (I left beforehand). That was my last contact with the head of the organisation. I have had contact with other team members (who were at the meeting) about ongoing work. It's a bit complicated as I'm essentially the only paid "employee" everyone else is a volunteer. I also have a lot of their materials in my home office as that's where I work from, and there's no "head office" for me to offload them to. Tbh, I'd guess he's hoping I might forget I wanted to finish up, and that everything will just plod along as normal...