Hi @Queenie,
I feel like I can understand a little of what you are going through. I think 5 weeks without an appointment, when you are supposed to be meeting fortnightly, is way too long.
Yes, I believe you should contact the support worker's supervisor and let them know about your experience, as they may not be aware that there is a problem. You cannot assume that they know.
If you speak to them or email them in a direct and polite way, then I don't think you are stepping over the line.
Recently, I got "dumped" by both Griefline and a social worker who I contacted through my Dad's hospice care group. ( a long story) On both occasions, they simply failed to make contact at the appointed time, and failed to call, they both just disappeared! I did not get any kind of polite apology or anything. I was just 'ghosted'. No text message , just nothing.
If I were really in trouble and needed them, I would definitely call and inform them of what happened. Or else I would contact a new, different service and go from there. As it happens, I am ok ( but no thanks to them!)
You can just say something like "I'm not sure if you are aware, but my appointments have been cancelled multiple times." And also "I think it might be better if I were matched with a different support worker, as this one hasn't worked out". It's fine to be pro-active... Just be gentle and neutral and stick to the facts... You don't have to make it like a real complaint.