If your cinnamon has tons of mealies it's not a happy camper and the conditions are not great for it. It may be a vulnerable plant to them and attracts them first before they go elsewhere (like : on orchids). You can try nettle manure, I did on the phals I had that were with mealies all the time in the last 2 years :
On top of the very nasty treatment I had come to (2 chemicals alternated) + the alcool/soap spray to kill on sight, I sprayed nettle manure 1-2 % all over the plants the first time, then at each watering for a month. The mealies sure did not like it and since spring (6 months now) the only phal with still a mealy showing off (2 in 6 months) is the one I forgot first hand…
So, since, for the phals save this peculiar one, no mealies (and no treatment since). First time in years I don't come back of holidays to meet a mealy congress.
Nettle manure is perfectly safe for us, will act as a strengthener and maybe repulsive at this concentration. It's used as insecticide at higher levels.
On the spider-mites front, there's neem oil. I have not tried yet as I'm cautious with it. It must be soluble (with soap added) it's important. And in a dusty/dirty environment (my case) you must clean the plants 2 days later, or dirt with the neem oil will clog the stomatas. It has other "virtues" so inform you well before use (it can lead to reversible male sterility, not good either for pregnant women). If someone who tried firsthand can give his input?