This is a non-delivery scam. Read How to Avoid A Non-Delivery Scam
As an example of what you could be dealing with, here are some Cameroon scammers that have been identified as living in Ukraine:
Stephan Nsansi
Abunaw Henry
Peter Fombang
Paul Ojong Ndip
Ayafor Trésor Zerewoh
Ify Peters
Valery
Peter Bide Nzegge
Charles Nganje
Innocent Peters, a.k.a. Ify
List of identified Cameroon Scammers
GARANT OIL
Odessa, Mikhailovskaya, 29/31, Ukraine
Tel.: +380 635 150 974 / +380 487 354 334
E-mail.: garantoil@mail.ua / garant.ua.oil@gmail.com
http://www.garantoil.com.ua (Non-Delivery Scam)
195.234.4.64
domain: garantoil.com.ua
dom-public: NO
mnt-by: ua.1gb
nserver: uns2.1gb.ru
nserver: ns1.1gb.ua
status: ok
created: 2016-07-09 21:17:20+03
modified: 2018-07-06 00:46:39+03
expires: 2019-07-09 21:17:20+03
source: UAEPP
registrar: ua.1gb
organization: LLC "1 GB"
organization-loc: ТОВ "1 Гб"
url: http://www.1Gb.ua
city: Kyiv
country: UA
abuse-url: http://whois-c.1gb.ua
abuse-email:
abuse-phone: +380445381588
abuse-postal: Ukraine 03035 Kyiv P.O.Box №32
abuse-postal-loc: Україна 03035 Київ А/С №32
source: UAEPP