I am just wondering where I can submit the abuse report if I experience any problems with services of my domain registrar in the future? Does anyone have such experience?

I dont think you can really submit an abuse report due to bad service. The only thing you can do is go with a different company. If they are really not acting fair you can try complaining to the regional registrar in question or ICANN etc. However they are not likely to take just bad service too seriously, since as a consumer you can just go else where. It depends what your problems were I suppose, such as if they stole it, you may be able to open a dispute with the local authority such as say nominet in the UK.