The nearly 100 complaints launched by Uber customers in the past year resulted in a failing grade for the car service.

The Better Business Bureau (BBB) gave Uber an F rating on its grading scale of A+ to F. A total of 108 complaints were made over the past three years and the majority dealt with billing or problems with the service.

"Consumer complaints allege misunderstanding Uber Technologies' pricing, being misinformed about the overall cost of the services rendered, and not being made a aware of 'surge pricing,' or temporary increases in the company's charges," the BBB wrote on its website.

Customers who tried to complain about these billing and collection issues found more problems with Uber's customer service.

"Consumer complaints further allege experiencing issues with the company's customer service such as having difficult reaching a customer service representative and consumers having their issues closed despite their concerns not being resolved," the BBB wrote.

Uber Technologies is not accredited with the BBB, which has aimed to provide verified, unbiased information on businesses, brands and charities for more than 100 years, according to its website. Uber started five years ago and now operates in more than 200 cities across 45 countries.

Uber customers made 54 complaints about problems with the product or service, and another 45 for billing and collection issues. A few other complaints dealt with advertising/sales issues and delivery issues. Uber also failed to respond to 39 complaints made against its business.

One customer was charged $710 for a 9-mile ride and claims Uber didn't notify the passenger about the surge charges put in place at the time of the ride. Uber's customer service initially refused to offer any refund, and then only gave the passenger a refund of $177.

"[The refund] is still not enough when the policy clearly states that I should be notified of the surcharges. $532.50 is still an outrageous price to pay for a 9.7 mile drive," the complaining customer wrote last week.

The car service cited its millions of rides taken across the world as proof that customers still appreciate its business, despite the poor rating.

"Uber's direct channel for two-way feedback is regularly reviewed and acted on to ensure a high-quality experience," an Uber spokeswoman told CNET. "The fact is that consumers in 220 cities around the world have made their opinion known by taking millions of rides with Uber."

Uber competitor Lyft also received an F rating by the BBB, but only had five complaints against it in the past three years. The BBB cited the lack of response to complaints as factors that lowered both services' ratings.