My mother used to make butter cream in all her recipes, and I adore it! but people in my country are not used to it, so when I make an order with buttercream people complian that it is something that they are not familier with. so I need basic frosting and filling recipe instead of the butter cream, knowing that its tooooo hot here, so whipping cream is not a good idea. thanks!

Ganache or fondant? Neither might keep up in the heat though, depends how hot is hot I guess. Royal icing?

Filling - preserve/fruit/curd or more ganache?

They might not be familar with ganache either but once they taste it not many complain!!

What is normal there or where are you?

Could you gradually introduce people to buttercream and then when they get to like it you will be the person to go to for the "yummy new filling/topping"?

the problem with the butter cream also that I cant manage its consistency in hot temperature, so when I feel it is good, i put it in the fridge, it became hard and not spreadable, and when make it softer, it melts out the fridge. we don't have shortening here (yes! believe it?!) so I should use just pure butter.
So I really dont know how to fix butter cream in summer