Finding the right infusion set for you is an integral part of insulin delivery and making sure you are getting the best from your insulin pump.
www.makingdiabeteseasier.com
If you can't order direct via the site I'd give them a ring.
Having said that, in your position I'd try to build up a backlog and order some more when you have over a month's supply left. (If you already do that and it's taking more than a month I suggest building up a two month's supply. And complain vociferously to your diabetic team)
In New Zealand there is a pump helpline who definitely have access to supplies. If you have such a number I'd try ringing it, otherwise the link above (company name Aire Liquide) has a helpline
0800 012 1560
Thanks for the suggestions. Yes those are the distributors that are late to send the supplies every time. I'll be traveling next week but I'll call them the week after for extra supplies. Also keep bothering my clinic with emails... it's really extremely frustrating.
A friend of mine also on tslim was in a similar position this week, ordered but a delay in the order being shipped and he was on his last cartridge, he called them on Friday and they said they were having problems with distribution this week and have fast tracked his order and put a couple of cartridges in the post to be safe. Not good they didn't communicate they had delays but at least they dealt with his call responsibly.