Hi Natalie, sorry we don't offer arm replacement service. We offer 3-month warranty on product, covering any possible defect in materials and workmanship. This warranty does not cover damage caused by accidents, negligence, or improper care. Please feel free to contact us if any question. 

Hi Jackie, Our frame comes with a fixed size. Choosing a perfect frame size online can be tough sometimes so we suggest that you could please check this link https://www.firmoo.com/help-p-1.shtml for reference. Thank you.
 

Hi Jackie, Our frame comes with a fixed size. Choosing a perfect frame size online can be tough sometimes so we suggest that you could please check this link https://www.firmoo.com/help-p-1.shtml for reference. Thank you.

Dear customer, So sorry but the frame comes with a fixed size and it cannot be customized. We understand that choosing a perfect frame size online can be tough sometimes so we suggest that you could please check this link https://www.firmoo.com/help-p-1.shtml for reference.  Also, we offer 30-Day Exchange&Return: Unsatisfactory glasses can be exchanged or refunded within 30 days of receiving. Only shipping fees will apply. Please feel free to contact us if you need. Have a nice day! Thank you.