sometimes the bug eggs are in the soil,get rid of that siol and transplant into new soil,it looks like p.h and heat problems to me are the tips off the leaves crispi.and if you cant get neen oil use garlic crush it up and mix with water and spray the plant it kills all bugs and it dont dammage the plant.you mite be sufforcating your roots cos that soil looks a little tight to me.good luck you need to talk to surreys princess or stinky cos they are the soil queens of canna