Different spell if interrupted

I feel like I should be able to make this work but haven’t been able to find a reliable way to do this. I want to be able to spam one button to use Slow when I am not arcane locked on my mage, and then when I am arcane locked, I want to be able to spam frostbolts. I triedto simply make a sequence for:
/cast Slow
/cast Frostbolt
And it worked sometimes but othertimes it would just default to frostbolt.

1 /castsequence Frostbolt, Slow Fall
2 /castsequence [combat] Frostbolt, Slow Fall
3 /castsequence [nochanneling] Frostbolt, Slow Fall
4 /castsequence [combat] [nochanneling] Spel, Spell
/ cast [nochanneling: Frostbolt] Frostbolt
/ cast [nochanneling: Frostbolt] Frostbolt, Slow Fall
/ cast [combat] [nochanneling: Frostbolt, Slow Fall] Frostbolt, Slow Fall
/ cast [nochanneling: Frostbolt: Slow Fall] Frostbolt, Slow Fall

Ggood day friend, I don’t understand English very well, but I’m trying to help you, if I’m not mistaken you want a sequence of several spells on one button, above I’ve given you options for how to do this, keep in mind that the spell that has a shorter recovery time needs to be written first Frostbolt Slow Fall but I think it will work like this because you have one spell streaming it needs to be cast separately /cast [nochanneling: Frostbolt] Frostbolt if I’m wrong, please correct me

I will give a few of these a shot and see if anything works, thanks. Just to be clear though, I am looking to use the Arcane spell Slow, not Slow Fall. I want to be able to slow a target and then if I get arcane locked from a spell interrupt, cast Frostbolt instead. Slow is an instant cast spell, Frostbolt has a cast time.

I wrote you just an example of what commands can be used for the sequence, and you already put your own spells under them, which you need and how you want, try a few varriants, I’m sure you will find one that works, good luck with your business.

@Scotch

There really isnt the option to do what you are trying to do. Your macro has no way of knowing if you are arcane locked. You can’t use a castsequence for this as if you are arcane locked it will never move on from Slow.

Your best option is to use a chained macro that has both lines as a separate cast and then Break the frostbolt cast manually if you don’t need it.