You can get the 10" filter housings separately from any decent wfp supplier cheap enough,.. £15 -£20 each if I recall right. It wasn't that the housings were bad quality,.. freezing will destroy the best of them, simple as.
The bad news is that freezing also knockers RO membranes, so it could cost you 3 new membranes too. Its an expensive way to learn to buy a cheap heater,....