This contradicts what they claim on their DDOS explanation here: https://www.ovh.co.uk/anti-ddos/mitigation.xml First question to ask them is why was their response different from what practice they advertise? That isn't cool. I would open a new support ticket with them and ask for an explanation since that happened to you recently.
If you need something low-cost and dedicated try their SoYouStart range, which is just their last-generation hardware. Going from a VPS to SYS is a huge performance jump for minimal cost. They have a higher guaranteed minimum bandwidth throughput than the VPSs and may get you better support possibilities. Cost is similar to a mid-size VPS.
Here is the result of the support ticket I had with them explaining that the traffic was not an attack and is expected to spike from time to time. Edited only to remove their upsell links.
"After looking into the matter, it would seem that our VPS do not have a profile that would accomodate your traffic spikes. However should you switch to a dedicated server, we would be able to apply a a custom profile to your server that we better suit your needs.
Our Kimsufi server are extremely affordable and do not cost much more then what you are presently paying. However they do have limitation, among other things, you cannot order additional IPs on the server. I would advise you to think carefully before purchasing such a server.
Another alternative would be to move to our mid range server, our Soyoustart servers, which offer many of the same benefits as our OVH dedicated servers, however at a very competitive price."
Sounds like their "Anti-DDOS protection" is bullshit for their VPS plans then, unlike the marketing statements all over the OVH website saying otherwise. :(
If you need something low-cost and dedicated try their SoYouStart range, which is just their last-generation hardware. Going from a VPS to SYS is a huge performance jump for minimal cost. They have a higher guaranteed minimum bandwidth throughput than the VPSs and may get you better support possibilities. Cost is similar to a mid-size VPS.