Unable to open world templates on iPad

Dear Sir/ Madam,
I wonder if I could report a problem of Minecraft on my iPad. Initially I have reported it to /feedback.minecraft.net./, but they referred me to Xbox center; Xbox center referred me to [Mojang Support (support@mojang.desk-mail.com); a person at Mojang Support (Carl-William) referred me here. 

What I'd like to report is as below:
I spent 300 Minecraft dollars 2USD) 2 days ago to open the world template "Bright Start". However, after I click the open button, it continues show "downloading....". I've waiter for a week and nothing changed, it makes me confused. 

Today I tried to used around 6 USD to unlock another world template "Build your own castle". Again, the page stuck at the initial page, showing "downloading....". It is pretty bothering, making people feeling that these are designed for cheating money. 

  In addition, I also checked my iPad storage space, and it's still enough. Previously I've used Minecraft dollars to open other 2 world templates, and they were downloaded within 1 minute, running well till now. My iPad was bought in 2017 and updated to the last version.

I have applied refund from iOS APP market, but I still hope someone can help to solve this technical problem, suggest the possible reason, or some tips to prevent it for the next time. I will appreciate for it. Thank you!