Try these and ask them about the condition for agreement
:
Flight Coordination and Control Center (FOCC)
TEL: +375 17 222 51 21
FAX: +375 17 222 79 54
SITA: MSQFCHX
AFTN: UMMDYAYX
Basically if the person on the phone won't know English, go ahead and write them a SITA and/or AFTN
Brgds.