I want to try their service. They also said they never failed on this field. Is this possible?

John, if this is not self promotion to the above site then I'd say their services are useless. Why would you want to improve Alexa in an artificial way? What the hell is Alexa actually? Everyone knows Alexa is one of the most irrelevant traffic measurement tools online as it tracks only the hits from people that have downloaded their toolbar so actually it doesn't show the real number of visitors.

Alexa rankings can be faked big time and I presume the guys at alexarankteam.com use a sort of bots that would give you a boost but bear in mind this traffic is useless. You won't get any sales or conversions so why would you go for that?

Personally I would gladly exchange 1000 alexa visits for one single true visitor that makes a sale.