COGAT stated that Gaza merchants suspended shipments because Hamas demanded a fee of 10,000 shekels ($3,220) per truck and required 30 percent of sales in cash.

From the articleIsrael says commercial goods not entering Gaza over Hamas tax disputeAlso in Israel halts commercial goods from entering Gaza; Hamas denies tax claims, Israel cites Gazan merchants angered by Hamas taxes as commercial goods stop entering Strip, Israel says entry of commercial goods into Gaza halted amid dispute between traders and Hamas | The National, Israel says commercial goods no longer entering Gaza after merchants suspend coordination | Reuters, BoP's Mladenov: Suspension of private sector goods into Gaza is 'unacceptable'