There is no limit mentioned when you signing up, about contacting sellers. But once you contacted a few, you'll be marked spam and sent through troubles. I never advertised anything, didn't mention my business URL, but merely asked the capabilities in terms of technology from the sellers. But I got black marked for no reason.
Keep off Fiverr. Or get them to make it reasonable. Horrible support at times too. They seem to run with no reasonable rules in place. For example in T&C they say even though your seller didn't deliver, you are obliged to pay the fee for the transaction. How ridiculous! You place order, you pay, and wait, and wait some more, seller doesn't respond, and he asks to cancel order. Fiverr say, oops sorry you need to pay me the fee! Because, T&C says so!
They REALLY NEED TO CHANGE THEIR RULES IN THE GAME WHEN FACING THE WORLD. These rules perhaps good for Israel, but perhaps ONLY for Israel, not for anywhere else where people are more honest and normal... I can't think of any other reason why their rules are so ridiculous...