My advise is NOT to trust that guy, I recently saw that he has several skype usernames, He has scammed me several weeks ago, I gave him time to "get the money" as he told me that he currently has no money.
Here's some screenshots of our skype talk:

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Basically he contacted me and we agreed that i would get him from diamond 4 to diamond 2 for 65 euros in 2 to 3 days, I was having problems so i couldn't really play the first day, no biggie, got him to promos.
He was playing ranked games on the account while I was boosting, I didn't really mind that he did and he even won most of the games, so he haggled to 40euros and I agreed. Sadly, he told that "his uncle is cancer" and my guess is that he wanted to say that his uncle has cancer, that was my main reason to give him some time.
The worst part is that a week after my boosting I saw him buying accounts, ect. Just wanted to make him lose some customers because of his lies.
Anyways, here's a tl;dr : Do not trust him.