I have searched wide and far and have not been able to find a single complaint about LottoSend that went unanswered. I was only able to find one single complaint on an online complaints board where the customer was confused about the shares per ticket for the Spanish Nacional Lottery game that he had entered through LottoSend, it seems that the ticket that he bought for $30 won him a $20 prize and he thought he was supposed to get a $200 prize, because of this problem he posted an online complaint saying that LottoSend might be a scam.
Other than this one single client I could not find any complaints. What is really nice though is that on the complaints board you see that an official representative from LottoSend writes an answer to the client and tries to help him/her with a refund.
There are some infamous online lottery companies with numerous complaints at online complaint boards where not even a single of the customer complaints goes answered by a company representative.
I personally can applaud LottoSend for only having one single online complaint, and for dealing with it in a professional manner. With hundreds of thousands of clients, having only 1 complaint seems really good. So you can rest assured that they are trustworthy and efficient in dealing with any issues or unhappy customers.