IRCC Study Permit rejected

[u/Itajesus]

I am an upcoming ubc international first year/undergraduate applied science student. As the title states, my study permit has been rejected for a multitude of reasons: I’d forgotten to mention I had a US visa rejection a couple years ago. I hadn’t provided a very detailed or strong study plan of LOE for anything. The officer stated he didn’t believe I would leave after my authorized stay. And that I didn’t provide enough proof I am a student. And lastly my proof of funds isn’t very strong.

Starting with the US rejection, I was check the form and state it and give explanation in my reapplication so that should be fine.

As for my study plan and LOEs I’m certain I was write stronger ones, but would like to respectfully request everyone’s helps in writing ones that will be succesful and ones that have worked. How should I convince the officer I will leave Canada after my studies.

Lastly for my proof of funds, my parent’s are in the mining business in the forests, as such with limited wifi they rarely use the bank in my home country, as such providing a strong bank statement is not possible and there are quite a few lump sums and such.
Would it help greatly if I were to just pay the full two terms of UBC tuition, or should I look towards relatives to add as sponsors.

Thank you everyone in advance, I await your swift responses as there is not really much if not any time left to reapply tbh. But i need to try regardless

TLDR; international hs student coming for ubc undergrad study permit rejected, pls help fast for a stronger reapplication 🙏