Another Guider here. After 3 weeks, I would have contacted the parent to see if their daughter would be returning. Waiting for 6 months is daft.
It does sound like the Unit Leader has paid census for your daughter (like others have said, ours was around the £35 mark per Member) and, with rent, craft, new programme resources etc she's trying to claw back the subs she could've made by offering your daughter's place to another girl.
However, it seems there are big issues in the Unit (a film every week?!) and maybe this is symptomatic of financial issues, lack of resources or little help running the Unit. Or, an issue in the Leader's personal life you're not aware of, making chasing parents for communication & payments difficult. Contacting the District Commissioner (details should be on your Brownie Started Form) may be helpful, even if you are not returning.
It is frustrating having to chase parents - tomorrow i have to chase subs for this term for 10 girls, and that's offering payment by bank transfer, cheque and cash!. Plus contact another who hasn't bothered come to a meeting this term (and they'll be at their third missed week by the next meeting). And that's on top of system admin, prepping activities, planning 2 camps, 1 sleepover, a County event and a Pack Holiday (running 4 Units due to lack of volunteers!)... I'm a lowly full time Mum of two, working full time, elderly parents & my own chronic illness, thank goodness my Husband volunteers too! But I do it to offer over 100 girls Guiding opportunities each week they wouldn't have otherwise.
I'm not unique, all Leaders are masters at juggling our Guiding and personal lives. But we're not blooming psychic - let us know if there are problems or you no longer need the space!