I am not sure if a negative rating is appropriate here. If EcuaMobi can sell off the domains at somewhat firesale/quicksale prices for an amount that repays principle + agreed upon interest + some amount for his time (that he spends selling the domains) + ~5% (for a late fee/penalty) then I don't think he can really say that he was really harmed, and I don't really think a negative rating is appropriate. An exception to this might be if EcuaMobi needed to give up and/or delay some work because he was spending time selling off the domains (this is a possibility because his Personal Text has said that he is not accepting new work for some time now - or it was saying that in the past).
If however he is not able to *quickly* sell off the domains for the above amount of money, then yes a negative rating is defiantly appropriate. This would even be the case if EcuaMobi needed to wait a medium amount of time to sell off the domains.
If EcuaMobi can quickly sell off the domains at prices described above, then maybe a neutral rating would be more appropriate to warn others about the lack of communication.
A quick sell for more than the loan plus interest is not the case, without any doubts. Until now I've been able to sell only one domain through
namecheap's marketplace and I've had no luck here (
https://bitcointalk.org/index.php?topic=1189756.0).
TBH I haven't been able to spend too much time on that sale as I've been very busy but it's definitely not an easy task. I hope I will get at least my money back but I'm sure it won't be fast and it may never happen.
If I get my money back plus interests in less than 2 weeks from now I'll make my feedback neutral. OP can help me sell the domains if he's interested at all.