The Messenger of Allah ﷺ as saying: Delay in payment (of debt) by a rich man is injunctive, but when one of you is referred to a wealthy man, he should accept the reference. (Using translation from Abū Dāʾūd 3345)  

قَالَ رَسُولُ اللَّهِ ﷺ «مَطْلُ الْغَنِيِّ ظُلْمٌ وَإِذَا أُتْبِعَ أَحَدُكُمْ عَلَى مَلِيءٍ فَلْيَتْبَعْ»