office box ticket sales expensive tickets Internet

I wanted to buy tickets for Imagine dragons and I don't remember how I ended up on "www.boxofficeticketsales.com"  I saw different prices on their website for General Admission starting at 49.99 but the list had so many different prices for same GA, I dediced to call to ask what the real price was, they told me since the event gained so much popularity prices went up to 149.50 for G.A + 30 lls of other charges. so I paid 360 dlls for two GA tickets. What bothers me is that GA tickets for this event are way more cheaper in other websites, I don't understand why the sell more expensive than the others for the exact same thing. Shouldn't there be like a standard for prices? I feel like I've been scammed.

Also I wanted to know what the extra charges were exactly for and they answered: "The service fee is charged to a customer to guarantee the tickets and ensure their timely delivery." Which I consider is ridiculous, even more ridiculous cause I received the tickets trough e-mail.