Abu Minhal reported,
Zayd bin Arqam and Bara bin Azib 
were business partners. They bought some silver, partly with cash and partly on credit. When this reached the Prophet ﷺ, he instructed them to allow what was paid in cash and to return what was bought on credit.
Ahmad 19307
Sahihحدثنا يحيى بن أبي بكير حدثنا إبراهيم بن نافع قال سمعت عمرو بن دينار يذكر
عن أبي المنهال
أن زيد بن أرقم والبراء بن عازب رضي الله عنهم كانا شريكين فاشتريا فضة بنقد ونسيئة فبلغ ذلك النبي ﷺ فأمرهما أن ما كان بنقد فأجيزوه وما كان بنسيئة فردوه
Its chain of transmission is sahih. Ibrahim bin Nafi is trustworthy and a precise memorizer, and his hadith is accepted by the group of hadith compilers. The same applies to the narrator before him, Yahya bin Abu Bukayr. This hadith with this exact wording was narrated solely by Ahmad, but a hadith forbidding the sale of silver for silver on credit has already preceded it.