Hi ! I had a big sale 8th april that I can see on my alamy contributor dashboard. But the amount of the sale, don't appear on my Current Cleared Balance. I use to be patient but more than a month seems to me unusual. Anyone else ? I can't find how to contact alamy contributor help.

More  than a month is completely normal on Alamy. It can actually even take several months till the balance is cleared. 

Right. Less than a few months would be fast from my experience. 

I wrote to Alamy support on April 12th about a sale from January 11th that hadn't cleared yet and from the boilerplate they sent in the acknowledgement email is this:

Seen your image being used but the sale is not listed yet?
 
Some customers report usages to us over a set period of time. If you�ve seen your images being used it can take up to 3 months to appear as a sale in your account. If you have a sale that remains unpaid beyond this timeframe please be aware that our credit control team will have a record of this and will be chasing the client for payment accordingly.

They said they were "still chasing" and hadn't forgotten about it. Possibly it was a coincidence but it cleared a day or two later.