Failure to deliver on time. Now withholding refund

In January we ordered a new oven to be shipped to Dar Es Salaam. The oven was to arrive in Dar in the first week of February.<br> Once there, there was problems with the paperwork sent with the oven. After weeks of back and forth trying to get said oven released from customs it was decided to have the oven sent back to the supplier. This had its own problems. During this time Steven agreed to refund the full amount to us. This refund was due in our account by 13th April. It is now 4th May and we still do not have our refund.