GSTR 7 and GSTR 8 QUERY

Any excess or erroneous amount deducted and paid to the government account shall be dealt for refund under section 54 of the CGST Act, 2017. However, if the deducted amount is already credited to the electronic cash ledger of the supplier(ie, supplier is  filed TDS credit received statement "), the same shall not be refunded.
Query 1:- under which head this refund can apply?
Query 2:- based on the above fact instead of refund, deductor can adjust such  excess or erroneous paid TDS against the subsequent month TDS liability if the supplier is not filed TDS credit received statement ?
Query 3:- Any excess or erroneous amount collected  and paid to the government account by the  e commerce operator then e commerce operator can apply for  such erroneous or Excess paid rax as a refund? Under which head can apply for refund?
Query 4:- based on the query 3, instead of refund e commerce operator can adjust such excess or erroneous paid TCS against the subsequent month  TCS liability if the supplier is not filed TCS credit received statement  ?