Is offering a daily Islamic tweet service, which includes a weekly competition with financial prizes (recharge cards) in exchange for a nominal fee deducted from subscribers via a telecommunications company, considered gambling or permissible?

If the amount deducted by the telecommunications company for the competition is the usual cost for sending messages, then there is no harm in the competition. However, if it deducts an amount greater than the usual, then the competition is not permissible, because it then becomes a form of prohibited gambling (maysir (definition)), where the prize money is collected from the participants' funds, making the winner a gainer and others losers. This is precisely what maysir is.