I am a Zimbabwean working overseas, Western Union is very reliable , u can send money by it.The only problem is the rate that is being offered , it is much lower than what is offered by the black market because the money is received in Zim dollars.If you want them to receive at higher rates, you have to contact pple with FCAs whom you can deposit the money in their accounts and then they deposit the money in the receipient's account number at higher rates.Like at the moment if you send by Western Union the rate against the USD is 6200 but the black market offers as much as 12500.
Post is not advisable.If you need more information contact me on my e mail.