renege
verb [ I ]
uk/rəˈneɪɡ/ us/riˈneɡ/to fail to keep a promise or an agreement, etc.:
Once the highest bid is accepted, a seller can be sued for breach of contract if they renege.
renege on an agreement/a deal/a promise The retailer claimed that the cosmetics company reneged on a deal to produce a range of beauty products for them.