Hi Bassline
Welcome to the forum! Glad to have you with us
I've been in a similar situation myself, and know how you feel. For a long time I was writing and sending to publishers, hoping to be picked up as a writer (I'm no producer though). Having not broken through myself, I don't feel qualified to give you advice, but here's what I think (in other words, I'm going to anyway!)
You need to expand your promotional activities. A friend of mine sat outside BBC for two days handing out his EP to DJs as the left work. He wasn't pushy or cocky, just said "I like your show, and I'd love it if you could play my music" - three of them did. You may not be performers, but does it matter? If you can get exposure on the radio, you'll find it gives you credibility when it comes to publishers.
Also, do you network with other writers/ producers? I'd find out who's doing what locally, and see if you can hook up with some like-minded people. So much that happens in the music biz happens because of who you know, so working on your network is never a bad idea.
The other thing would be to find an up-and-coming singer or group that you can get involved with in a writing capacity. If there are any agents/ managers in your area, you could see if you can get involved as writers for some of their acts.
Plugging away at publishers and labels can be punishing at best, so finding other ways to open different doors sounds like something you could really benefit from and enjoy. Of course, don't stop sending your work out; just do other stuff too.
Hope you decide to stick around on the forum.
Tone