Get a contact email from the customs office, then explain the problem to the bike shop you purchased from, and ask them to send an email directly to the customs office stating that you spent $50 or something like that.
Customs taxes are so dodgy. You've already paid 5 hidden taxes minimum, all hidden in the total cost of the product and shipping. You paid tax on your money you earned, then hidden taxes from the manufacturer, the bike store and both countries shipping companies.
We go to work to earn tax to pay taxes because we get taxed on our taxes. Its attax.