Clinics won't inject my testosterone. Where do I get syringe/needle?

I have a prescription & receipt from my doctor in Thailand for an injection of Nebido (testosterone undecanoate). I've been traveling the last 3 weeks and it's time for a shot. I wanted to go to a clinic to have them poke me in the butt, but after visiting 2 of them, I was denied. So.... I guess I'm left with doing it myself. I can't find any info on pharmacies that sell syringes/needles. Any recommendations on pharmacies that sell them without any hassles?

A lot of clinics are directly associated with pharmacies, usually on the same premises.  Have they suggested that you purchase a new vial from them?

No. No suggestions given. Just a "Sorry, the Dr. can not give you an injection. That is not from Vietnam."
"I have a prescription."
"Sorry. We can not help you."

I have bought 2.5ml syringes and 23G needles from two small pharmacies in Nha Trang, no issues.If they have something, they'll sell it to you. PM me if you get stuck (no pun intended) and I'll see if I can locate one of the places on Google Maps for you.