The 0.45ohm Notch Coils are not easy to find, especially at a US vendor, and at a reasonable price. Some China vendors have them. But they’re either not well-known sites or aren’t available at reasonable prices (especially including S/H from them). I personally wouldn’t buy from them.
So, if either or both of you are interested in, and/or want to keep using that tank and those coils, I’d:
1) Buy all the coils you can afford to buy from ProVape while they still have them. JoyeTech isn’t making them any more.
2) Watch the video below and learn how to rewick the coils, so you can extend the life and use of each coil that you DO buy.
For the longterm though…you also have several options.
Choose and buy an alternate tank or 2 that takes drop-in coils that are popular and are still being manufactured. The Innokin Z-coils work in a number of very popular Innokin Zenith tanks and the 2 different sized Innokin Zlide tanks. The coils are available in a large range of ohms, too…from 0.3ohms – 1.6ohms. Many people get 2 weeks or more of use from each coil. (I can give you info. on where to get those tanks and coils at the best prices, if interested.)
Or, if you don’t want to have to buy and stash many drop-in coils…choose an easy to use RTA or 2 (rebuildable tank atomizer) and learn how to make, install, and wick coils. The supplies you’d need to do that are not expensive and are readily available.