A small fashion seller running a shop out of a spare bedroom does not have a call center, a dedicated CRM department, or a six-figure software budget — what they usually have is a smartphone, a WhatsApp Business account, and whatever loyalty they can build one reply at a time. This study examines how three mobile-based customer relationship management (mCRM) strategies — personalized communication, service responsiveness, and loyalty program management — shape customer retention among customers of local fashion micro, small, and medium enterprises (MSMEs) operating in online marketplaces, with customer satisfaction positioned as the mediating mechanism that determines whether these strategies actually translate into a lasting customer relationship. Two hundred customers of local fashion MSMEs were surveyed using a purposive sampling technique, and the proposed model was estimated using covariance-based Structural Equation Modeling (SEM) with the LISREL software. The results show that personalized communication, service responsiveness, and loyalty program management each significantly and positively predict customer satisfaction, which in turn significantly predicts customer retention; service responsiveness and loyalty program management also retain significant direct effects on retention, while personalized communication's effect operates almost entirely through the satisfaction pathway rather than directly. Customer satisfaction was found to partially mediate the relationships between service responsiveness and loyalty program management with customer retention, and to fully mediate the relationship between personalized communication and retention, suggesting that a friendly, tailored message can only keep a customer coming back once it has first produced genuine satisfaction. These findings extend mobile CRM theory into the resource-constrained MSME context and offer practical direction for small fashion sellers deciding where to invest limited time and budget within their mobile-based customer management efforts. Keywords: mobile customer relationship management; personalized communication; service responsiveness; customer satisfaction; customer retention