I have not used their service, but to add to the discussion about bad grammar and it apparently not having a technical person running it, all of their MX records point to the same IP, and even worse they point to CNAMES. MX records should point to A records in DNS, not CNAMEs.
;; ANSWER SECTION:
lus.com. 29m31s IN MX 10 pop.lus.com.
lus.com. 29m31s IN MX 20 mail.lus.com.
lus.com. 29m31s IN MX 30 smtp.lus.com.
;; ANSWER SECTION:
pop.lus.com. 27m43s IN CNAME lus.com.
lus.com. 27m43s IN A 97.74.200.44
The reverse DNS points back to secureserver.net . The reverse DNS does not have a custom PTR record.
;; ANSWER SECTION:
44.200.74.97.in-addr.arpa. 1H IN PTR ip-97-74-200-44.ip.secureserver.net.
The IP addresses don't appear to be blacklisted.