Question about visa transit

Hi, my husband and I went through your website to get our visas for  Vietnam from the USA. Our approval letter is good from November 17-  December 17 but on the visa it only says valid for single entry. We  entered Vietnam on November 17 but then went to Thailand and will be  flying back into Vietnam from Cambodia. We have a 12 hour layover before flying home and we’re wanting to go out into Ho Chi Minh and walk  around. Is this going to be an issue since we only had a single entry?  Do we need to apply again to walk around for a few hours? Please let me  know as soon as you can so we can apply for new ones if needed. Thank  you!!

 Morgan Yerry

Dear Morgan,
We are afraid that you will need a visa to enter Vietnam from Thailand. Once you go through the customs at the airport, the visa is required even it is just for a  few-hour visit.
Please let us know if we can be of any further assistance