When you call back they have a recorded message that claims they we were calling on behalf of "All Kind" from "The Fundraising Centre". With the number of calls they make and the variety of numbers they come from there is no way in hell this is legitimate. It is actual spam. Block them, and all of the following numbers they also call from:
(07) 4243 6993
(07) 4243 6991
(07) 4243 6910
(07) 4870 9297
(07) 4870 9225
(07) 4870 9223
(07) 4870 9216
(07) 4870 9200

I've received calls from this number, (07) 4870 9200, (07) 4870 9216 over the past few days. All to voicemail. Never a message left. Unsure if a (legally allowed to call) charity or a scammer. Could be either.