chances it's an design fault as the soldering on usb port to pcb is very weak, might as well throw it in the bin, especially considering :-
checked the local hk Chinese forum, zopo renowned to break down very easy
buy a new phone, has 12 months warranty,
2015, you can get a decent phone inexpensive with much higher specs, ie, sony xperia e4 ( HK$1099), moto g HK$1500, acer liquid HK$1350 etc, more importantly, better build quality
ACER Liquid X1 - Smartphone 智能手機 - 手機 - 通訊 - 香港格價網 Price.com.hk
Sony Xperia E4 - Smartphone 智能手機 - 手機 - 通訊 - 香港格價網 Price.com.hk
one of the reputable sellers CCAV listed ( I have purchased 5 TV's ,for myself, boss and family, my wife sony xperia z1 compact last year, sony camera there)
China Club Audio & Video
10/F, Yau Shing Commercial Centre,
51 Sai Yeung Choi Street, Mongkok
電話: 2787 7992 / 2787 7993 , 傳真: 2399 0070
it's a 2013 phone, prices and choices are much better, nowadays.
if you spend HK$399 on a repair, what happens if it breaks down again in a few months
check out the buyers guide for mobile
GSMArena smartphone buyer's guide: February 2015 - page 3 - GSMArena.com