Is it permissible to sell goods by installments with the condition of a bank deduction that incurs fees, and is this commercial transaction permissible?

If you have taken possession of the commodity, there is nothing wrong with selling it, even if it remains in the seller's warehouse. If you have not taken possession of it, then it is not permissible for you to sell it until you take possession of it, due to the Prophet's (peace be upon him) prohibition of selling commodities before possessing them. As for bank deductions, they are permissible, unless they are through an usurious bank; in that case, it involves assisting in sin. There is no harm in the bank taking a specific amount for the deduction process. The sale of the commodity by the person who buys it from you to the owner of the warehouse is permissible, even if it is for less than the price he bought it for, as this is one of the permissible forms of 'inah (buy-back).