Fault of Huawei

My phone was just over a year old working perfectly fine until i plugged an aux cord in it, and the motherboard blew up it happened to many others, i sent my phone in to huawei to check what was really wrong ,and unfortunately i didn't have the receipt but i assumed they'd pick it up with the IMEI number,all they gave me was a receipt to say that the phone was booked, all i asked them to do was check the phone not to fix it, i had no calls from them to say what was wrong i had to go to Huawei during my working hours ,and the second time i went they told me they fixed the screen which had a small crack, all of that which i didn't ask them to do. i went and they tell me that my phone is fixed and i need to pay R4600. Firstly, There was no communication from the huawei store on what had happened to the phone until today.I paid R6000 cash for that phone and now i need to pay R4600 to get my phone back when in all honesty this is a fault of huawei?I find this ridiculous Went to huawei again.so apparently they **** that they fixed my phone.. they then told me it'll cost R2000 to fix.. previously they charged me R4600 and they told me that the phone was already fixed... Is this the type of service to expect from a reputable company such as huawei?? I have literally no funds, Again do I really have to pay for something that wasn't even a fault of mine?? There was no water damage, all it took was an aux cord. That phone was just over a year old.