Tds deducted after 1.7.17

Some buyers had deducted TDS under GST sales from one seller during the period from 1.7.17 to 31.03.17. Both the parties acted under complete ignorance of extant rules. the amount of TDS is being held up by buyers. Can the seller take any benefit of that of the TDS in the accounts for the period from 1.7.17 to 31.03.2017. Please advice me. What would also be the status of TDS deducted in the pre-GST and shown as receivable in the books of seller during post-GST period?