the bank lost the check i deposited on my acct

hi good day, i just want to get more info on what can be my options, i deposted a check iao $6000 in my acct thru interbranch..it was received and when i updated my acct, however after 5 working days, the bank called and informed me that they lost my check..i was very upset and i checked my acct online and it is still posted on my account and up until now...however i got several calls and asking me to ask the issuer to make a stop payment on the check, the issuer refused because he said it was already funded and i did not lose the check but the bank and its their responsibility and he is out of the country...what options do i have because i need the money on dec 5 where it is due to clear and what can i do to make the bank accountable for this gross negligence....thanks!