Is it permissible to replace a damaged phone part with a commercial (Chinese or counterfeit) part if the original is unavailable, and is that sufficient?

Maintaining mobile phones falls under the category of a joint employee (اجير مشترك). Such an employee guarantees what is damaged by his action, even if without negligence, as agreed upon by jurists and the early generations, such as Omar and Ali (may Allah be pleased with them both). The rule for guaranteeing damaged items is that fungible items are guaranteed by their like, and non-fungible items by their value, based on the Prophet’s (peace be upon him) hadith (definition) regarding the incident of the platter. So, if a worker damages an original part of a phone, he guarantees it with an original like part. It is not permissible to replace it with a non-original part except with the customer's consent. If an original part cannot be obtained and the customer does not agree to a non-original one, then the guarantee is the value of the original part in the nearest market. It is necessary to inform the customer about the damage, even if a new original part is installed, for several reasons. However, if a used or counterfeit part is installed, it is definitively obligatory to inform the customer.