Is one considered sinful if they commit to paying the agreed-upon rent of 50 riyals, after the landlord breached their agreement and refused to reduce the rent from 100 riyals to 50 riyals after the first two months, based on the noble Hadith "Muslims are bound by their conditions"?

If the landlord and tenant agree on a specific rent and a known duration, the contract is binding, and neither party may unilaterally terminate it. However, if the lease duration is not specified and the contract is renewed monthly, then the contract is binding for the current month and permissible for the following month. In this case, the landlord or the tenant has the right to request a rent adjustment before the start of the new month, and whoever does not wish to continue has the right not to renew.