I had the same kind of problem with them
the main problem is very very very low I/O perf, which seem to come from the server design.
I think their servers are very good for the price (SC and XC models)
all you have to do is open a ticket, tell them to check the HDD perf, if they see a problem they will change your server, as soon as your new server is up, open a new ticket to ask them to check the perf again, if the perf are low ....change of server again, until you are provided with a correct one.
You can check by yourself
dd bs=1M count=64 if=/dev/zero of=test conv=fdatasync
64+0 records in
64+0 records out
67108864 bytes (67 MB) copied, 0,773044 s, 86,8 MB/s
this is a correct value of write speed, if it's lower ask them.
I think it's worth the trouble for the price