Should i ask for a refund?

[popopboat]

Hello, so i bought LTC3780  step-up/down converter, and after hooking it up it died in 2 minutes of "use", i did not really use it just connected it to input battery and checked voltage at output so no overloading done or shorting it out, but it died, 2 mosfets burned out, and it is now useless.
i contacted seller and he said "sorry, we resend one to you,ok?" ... found it fishy but ok , and i said that i would be glad if he would send me another ojne, bla bla, and that i hope he would not scam me and if he could send me a proof that he actually sent me ...and then he said " OK " ...nothing more nothing less...
so i dont know what should i do now? wait ? or asking for a refund? and could i get a refund because it died without my interference 😕

[repairelectronics]

Is this the standard $15 converter from China? I've bought a few over the years without problems, you just happen to have gotten a bad one. How long did it take to get to you in Croatia?

I doubt the replacement will get to you before your eBay MBG runs out so it is always best to get a refund first and then repurchase the item. You only have 30 days from delivery to start a defective item case or you would have to pay out of pocket for return shipping including tracking which in most case can be several times what you paid for the item.

[popopboat]

It took about 20 days, 
yeah i know that it is mass production and sometimes there are problems with items and/or shipping and because that im not really angry or anything, i can wait, but i would like my item in working condition 😕

Seller said this "i will resend it this week and upload the order number to ebay,you can see the handle info." and 
Today i got AGAIN notification  that my item is being shipped, but info and tracking number are same (even delivery dates) just like last time/first time i ordered it so what should that mean?

Estimated delivery is to March 3, 2019  and as long i know i have 30 days of last day estimated that would be 3, April? Or 30 days of the day that item arrived? Then i doubt that i have enough time for refund request...