Have you tried bead-beating in a tissue lyser? it usually works, also I use the Solution D from Chomczynski and Sacchi, 1987, I guess you can find the recipe anywhere (I will also put it under https://www.researchgate.net/group/Methods/files where you can also find other protocols but there are somehow not many) . The solution is a bit nasty to prepare but it keeps for a long time, it's waaaay cheaper than Trizol and I have the impression that it works better.