Contractual Breach & Zero Response

I asked Cell to cancel my Contract and was informed there is a 30 day notice period despite my contract stating it is a 20 Day notice period (Section 4.3). They also breached the contract by not advising me 40-80 Days before the contract was due to lapse (Section 4.2) in which time I would given them the correct notice period. Blatant breach of contract from their side, multiple phone calls and 3X promises that a team leader would contact me back regarding the matter with 0 response.