Yeah, I'd agree that for this and with us not knowing how it was built, what the conditions are, or even if the original setup was correct this is not necessarily a DIY repair.. It is possible that it came out because it wasn't adequate to begin with and there might be some damage you aren't aware of if it was properly setup but was damaged by wind... And if it was weather related and gets pricey you might be able to file an insurance claim.
Service mast support requirements seems to be something that varies by local jurisdiction, but it seems like what I've seen when I've searched in relation to my own project is that guy wire support is required when the mast extends more than 30" above the roof, and when it's required they want to see it in a V shaped with particular requirements on maximum and minimum allowed angles and so forth and there's load ratings for the wires, the attachments will have anchoring requirements and there should probably be a plate or something... Fixing it right probably will involve someone that knows what they're doing, and doing less could mean it breaks again and you might end up with a mast falling over and hanging down to the ground.