Could try to diagnose what the problem is but the bottom line is, "it doesn't work" and your own options for repair, cost wise, are next to none. Like so many things "imported" that sell for very low prices the one caveat is with "repair options". The cost just to take it apart is almost that of replacement, hence, specific parts are probably not even available. That is both good and bad. The good being, the cost to replace is low. The bad being the "hit or miss" nature of cheap imports. If nothing breaks, it's a damned good value, if it does, well......

I myself wrestled with that knowledge and I finally opted for a used Nikon SB600 in very good condition. Cost was about $150. Was it a better value? So far, after a year, I am very pleased but honestly, only time will tell for sure. My choice was largely based on experience back in the '80's. I had a higher end Vivatar that developed a leaky capacitor early on. I also have 2 Nikon SB16's from the '80's which I bought used back then, and they still function today. I'm not going to tell you that's the way to go. You've still got $100 to match my $150 spent to determine "value". You just have to decide which way to go.

PS: I use Nikon. If you use Canon I would "assume" Canon flash quality to be on par with Nikon but I honestly don't have first hand knowledge.