Ridiculous customs because we are desperate

I would like to understand why imile is charging so much on customs it’s more like a ripoff I have a friend that had 2600 on her order in total paid 840 at buffalo I paid 2400 but I had to pay 1154 on customs that like half of my order I saw it last month when I had trousers amount to less than 300 delivered by imile and I had to pay 117 on customs can I get a breakdown of how they get to that much.